Misfire Under Load No Code

I pull over, shut it down, wait a couple minutes, restart, and it's working fine. Engine runs smooth every time it is started. If you prefer the DIY route, you can purchase a code reader and run the scan yourself. went stage 2 at 115, went vf39 at 155. hello friends i have a noggy blue audi s3, 2000 plate, revo'd and forge dv007p (or something) my car started misfiring whilst i was driving on the motorway, no engine management light, misfire only under load when accelerating hard. 8 - 1 CR? Should I try mixing the gasoline with turbo blue? Could that possibly be the problem? Any way a bad torque converter would cause the vehicle to act like it was "missing" or "sputtering" right around 3000. This system first became available on passenger cars in the 1995 model year and 1996 for light trucks with a gross vehicle weight of under 8500lbs. There are no air or oil leaks in the engine bay, it doesn't overheat or loose any coolant. Also, it may run fine most of the time but suddenly misfire or cut out for no apparent reason. Engine Misfire : Buick LaCrosse 3. Also, the miss fire only occurs when the engine is under a light load (like trying to maintain 45 mph in 5th gear, feathering the throttle) if you accelerate hard it runs fine and 70 mph on the expressway it does fine, its only when its warm under a light load that it missfires. After the misfiring and vibrations which are very noticeable the ses light illuminates and when checked with a scanner reads the p0307 code for misfire on cylinder 7. I am currently trying to fix my mothers 1998 Nissan Pathfinder LE 135,xxx miles which is randomly misfiring at idle and also under any load. 04 Jetta GLI Catless Turboback exhaust Neuspeed Tune Intake AWE Diverter I picked up a GLi which seemed to run pretty well on the test drive. Now, until the service, there wasn't a misfire that I had noticed - but this was very obvious, at high revs in a gear we were bunny hopping all over the place. But theres no check engine light at all. no luck, still misfires the same cylinders in the about the same percentages. Truck is misfiring only when driving with a load. P0301 Cylinder #1 Misfire. It runs fine under load but I can feel an obvious misfire when idling and it stumbles around 1800 RPM with 1/8 throttle input and under. Run a code check. Under load (when in red on the boost), I get a misfire which will pop a code (cannot remember which one it is - will find out later). It misses and bucks until you depress the pedal enough for it to kick out of overdrive. Symptoms of a misfiring engine. 8 - no codes/no check engine light Here's a quick video: YouTube Hit the throttle and it stutters, misfires, no power. try swapping plugs and wires from 4 and 6. Hi guys, think I may have found my misfire problem. With the computer conected we monitored the live data and were recordeing most of the misfires in cylinder 6, 4, 2 with an occational misfire on 5. Recently I started noticing a misfire under load while climbing a hill with speeds between 60 and 70mph. 6L Misfire, Rough Idle, Code Misfire #3. inlet manifold seemed to be dirty with oil ? have ordered new crank case breather valve for tomorrow. The only mods done is a pod filter, FMIC, bigger fuel pump ( unknown brand or type), 3 inch from the dump and a manual boos controller which is wound right down to stock boost. I've recently found that under hard acceleration, the engine starts to misfire around 5000 rpm, as if the rev limiter is kicking in. Marlin Model 70 misfire My 1985 model 70 has been a flawless compainion until lately. Come along on this mobile diagnostic call to diagnose a misfire on a 2008 F-150. anyways took it to a local garage said it could be spark plugs replaced with ngk platinum - drove perfect for 5 minutes and started misfiring again. I've tried 2 sets of plug wires. Need some ideas. Unlike most, the P30x codes clear as soon as the condition stops, but they do leave the code and freeze frame in memory IF the light has come on, no matter how briefly. literally like no power under load I cant speed up hardly to get around someone now. With the CEL on, the car will hesitate if I give it any throttle, but will run smoothly if I feather the gas. Power is provided to the coils on the white/violet wire. 8 - no codes/no check engine light Here's a quick video: YouTube Hit the throttle and it stutters, misfires, no power. 3 ms at idle for NA engine), and DTC code P0171 may be set. Was running fine for about half a day and then started misfiring under load Took it home and checked the cooler. but I'm learning!. CYLINDER CONTRIBUTION Other Misfire Diagnostic Methods Other Misfire Diagnostic Methods The example below shows the upstream and downstream O 2 sensors for both banks of a Ford application with a V6 engine. P0300 Random Cylinder Misfire. VW Polo 1999. These misfires do often come under load from the engine, and you have the most load on the engine when you are accelerating on higher RPMs and higher gears. Low RPM misfire from 1k-2k RPM's PLEEASE HELP!!! Frustrated. So I put the old coils back on the engine and pulled each one with the engine running. I hear a vacuum leak at the back of the engine. 7 tdi missfire, vectra c ctdi splutter low revs no load, Zafira b 1. The camshaft sensor code and the fuel supply code have both stayed gone. An ignition system problem is one of the most common reasons for an engine to misfire. The Bakes technical resource library "FuelPumpMaintai n" item may help you too. Or, it may start and idle fine but then misfire or hesitate when it comes under load. ok, i have a 2004 murano 3. I have a misfire at idle and low load/low RPM. com News & Notes. Under normal circumstances, you’d. I have had no check engine lights come on, and when i feel it misfire i have slammed on the gas to throw a code out and. If the misfire problem has gone away and does not reoccur on the second or following trips, the OBDII system may erase the temporary misfire code and forget the entire episode. Subaru Legacy GT-B e-tune intermittent misfire and hesitation under load. this week: stutters under load (like 35-40 mph and try to pass) engine light flashes and goes off, you can repeat this at will. Letting go of the gas a bit made the misfire stop and the flashing light disappear. 5l GTDI misfire under load × Help us help you. I had it checke dthe other day and the codes showed an intermittent misfire on the #3 and 4 cylinders. I replaced the #3 coil pack, with no improvement. I had it at the local mechanic and he thought it was a plug lead so, I changed them. Note: Be aware that the #1 cylinder misfire code is a catch all. 4L engine, misfires under light load about 1200 rpm/52 mph Was worse on a rainy day after setting a couple days, so it was cold, likely damp But otherwise the 52 mph, light throttle misfire has been masqueraded somewhat, by maybe potholes, until I pinned it on smooth pavement. The misfire is only happens above 2500rpm but then it's quite bad. Let's turn the page and we'll take a look at what you'll need to do to pinpoint and resolve the issue causing the misfire. It turned out to be a bad coil pack. 2004 - 2008 Ford F150 - 2006 F-150 5. Sitting on the trailer, it revs and idles fine, but misfires under load in the water. 7L Engine Miss. A good friend phoned me from King of the Hammers last year, sharing that his late (2004) TJ Wrangler 4. I looked at the valves through the intake ports--they are REALLY filthy. Some chunks of carbon are hanging onto the stems under the tulip. So isolated misfires won't trigger it. I have a 1997 Ford F-250 4x4 with a 4. ) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more. I believe this slight "threshold" effect may explain why so many people report intermittent, random misfire or " bucking " under light load at low RPM (45-55 mph), with NO code set. It seemed like the misfire would get worse with the more fuel you were giving it. Another common reason for misfire is spark plug gap. As mentioned earlier, the general causes of a misfire fall under the headings of 1. But today you're up for a good challenge and you can't get to the gravy work until this job is done. If the misfire problem has gone away and does not reoccur on the second or following trips, the OBD II system may erase the temporary misfire code and forget the entire episode. It was also using tons of fuel, so I was led to believe it was the Lambda sensor. Letting go of the gas a bit made the misfire stop and the flashing light disappear. I wonder if this sensor could be. The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. P0300 P0306 Misfire fixed - fuel injector '99 4Runner the codes and it showed P0302 Misfire Cylinder #2 and P0171 System too lean. '04 Dodge Ram 1500 misfires when engine is under load ? I love my Ram and general driving around town is fine but on the open road when accelerating hard the engine misfires as if I'm a cylinder down. Mentos Earn this. So isolated misfires won't trigger it. I even changed the egr,new ecm,new intake man. 05' Random misfire and no power (4. 4L constant misfire fixed!!!! - Ok guys, this is a log of my misfire nightmare. 5 liter V6 EcoBoost engine) without needing to block the intercooler, allowing it to continue running at full efficiency. The live data from the scanner will show a misfire count per cylinder. Stinger-Performance. The code also may be erased if no misfires are encountered under similar driving conditions during the next 40 drive cycles. Idols 100% fine. I had it Scan and there is no code also, nothing showed on the cylinder misfire calendar. 0L Rubicon engine would not idle on a hot restart. But today you’re up for a good challenge and you can’t get to the gravy work until this job is done. Homo, Gamer, Writer, Dungeon Master, just making my way along my path to spiritual enlightenment and looking for like-minded peoples to join me. I have moved the coils and plugs on both cyl. not sure but maybe a bad coil could fail under load and cause your problem. They seem to occur for no apparent reason. 6L Misfire, Rough Idle, Code Misfire #3. I'm going to take the upper plenum off since there are only two blots left and the upper gasket set includes it, but I'm going to wait until I hear something on the lower. ( Audi S3 8P TFSI 2010 Model ) I have recently within the last 12days noticed my car was feeling a bit under power , and the exhaust was given out some funny noises. Unfortunately, each time the vehicle was investigated and fault codes cleared, no problem could be found with the usual suspects (oxygen sensors, knock sensor, etc). the engine to misfire causing a. I lost sight of her so I pulled over. Already replaced wires and plugs. It has developed a misfire when hot and under load. 4L Lincoln Navigator Cylinder 8 Misfire, Liquid in the Dwell, Stumped. Further information from the customer indicated that the truck misfired the worse in drive, not overdrive, at light to normal cruise around 2000 rpm to 2500 rpm. Re: Hard Misfire Under Load plugs changed the problem is the platinum plugs. A vac leak would cause mulitple cylinder misfires or least one under load, this is missing at idle same with a EGR sticking close/open. My problem is a bad (and getting worse) intermittent misfire, especially @ 1500-2000 rpm under load, but also can feel it at idle. Lack of power when cold under load) Replaced the tappit erased the fault code all now solved a cheap and easy fix. I have a 2007 Silverado classic With a 5. I'll have to drive on the highway to check it under load later in the week. Rich plug = O2 sensor /conn/wiring etc prob (should have a Code in KOER), ECT Sensor prob (code too) Spark Plug Firing End Analysis, General Source: by gnttype. com News & Notes. New plugs, coils, fuel pump, filter in the last year All motorcraft parts except pump and filter. Engine runs smooth every time it is started. When retrieving trouble codes, only consider related codes to a specific misfire problem, like an ignition coil failure code. com! You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. I did a fault code check. literally like no power under load I cant speed up hardly to get around someone now. Stinger-Performance. misses when cold then lack of power under load. Had this jag now for 3 weeks &thought we solved the problem but just returned to us again now it all started with it misfire/heavy judder under extreme load/speed but progressed to random times,had codes P0303 cylinder 2/3 misfire,P0353 ignition coil c primary/secondary cicuit & P0303 checked out oxygen sensors & changed all under customer. I have a misfire at idle and low load/low RPM. Always begin any intermittent misfire diagnosis by using your professional scan tool to retrieve misfire codes and freeze-frame data. The repair shop had diagnosed the coil pack as faulty and fitted a new unit with plugs, but this made no difference to the problem. 3 with 116,000 miles. under heavy load (pulling a hill) I have replaced the fuel filter, air filter, cap, rotor, plugs and wires no change I also replaced #4 injector no change. A misfire could be the cause of your engine vibration. My 93 cbr900rr runs great choked, and unchoked under load or throttle. If the problem persists more tests needs to be done to diagnose the problem, see "Possible Causes". No other codes. The funny thing is - the car would do fine if I drove for a while. I suspect there may be a base engine concern, but I have never seen such a problem with V10's. Plugs are black on 1 & 2 and not that black on 3 and 4 but were wet. Always prove out your diagnostic theory completely, and bear in mind that a malfunctioning EGR system, a faulty fuel injector, or compression problem can mimic ignition component failure and cause the PCM to store a misfire code. I also notice a slight stumble on take off in 1st gear. To diagnose an engine misfire on a Mercedes all you need is a generic OBD II code reader that can be bought in some cases for under 20 at your local auto parts store or on Amazon’s Best Selling OBD II scanners list. Still misfiring under load/acceleration and getting worse. Replaced plugs, wires, rotor, fuel filter, distributor cap. Decided one day to run a test with my scanner hooked up while recording the misfire data from the cylinders. Both were cylinder 3 misfire codes. Can you try a Test for Codes? Self Test by BroncoJoe19 do the KOEO = Key On Engine Off portion first & Remember to have engine @ Normal Operating Temperature before doing the KEY ON ENGINE RUNNING (KOER) portion It could be due to a problem with the EGR system (other than the valve itself) causing the engine to misfire under load. 2006 Ford F150 4X4 5. GSX-R1000L4 Misfire / bogging down under power Its a standard bike, no modifications other than a slip on can. This engine will sometimes completely fail to start when it gets hot enough. Sent from my DROIDX using Tapatalk 2. For instance, here is the language used in two of the NHTSA Recalls for the 2007 Odyssey:. First thought was to pop the hood and look and listen for vacuum leaks which we did as this would be the most common cause of this idle and surging condition. Letting go of the gas a bit made the misfire stop and the flashing light disappear. Further information from the customer indicated that the truck misfired the worse in drive, not overdrive, at light to normal cruise around 2000 rpm to 2500 rpm. Start by checking for intake leaks, intake gaskets are a common caused of multi-cylinder misfiring. I turn the truck off, allow it to sit for a few minutes, whip out the code scanner, only code that was there happens to be P0300. 7 horror tech random misfire 12-18-04 08:13 AM - Post# 577461 In response to mikhalljr I have a 98 Tahoe, 5. A gap that is too large may prevent the plug from lighting when there is a dense mixture in the chamber under boost. , P0301 – P0308). I have a '94 4x4 silverado 1500. Drives fine. Search My Stuff. The misfire under load has always proved Login to read more. It is 100% stock. Exterior; Autolamp automatic on/off headlamps; King Ranch F-150 fender badge; Vinyl upper door trim panels w/integral armrest, front/rear map pockets, courtesy lights; Heating, Ve. The funny thing is - the car would do fine if I drove for a while. 4L 2V engine. Since the only definite way to diagnose this is with an oscilloscope, which few people have including mechanics, replacing old worn out parts is usually the easiest fix. Put the ignition switch in position 0 and wait till the load relay drops out. Now it seems like I have a pre turbo exhaust leak at on the passenger side (i say that because thats where the popping/backfire is loudest) and I have a rough idle and cylinder 4 misfire and cel that flashes/stays solid/flashes/stays solid/flashes. 9 judder , judder and misfire under load, astra 1. I even changed the egr,new ecm,new intake man. This is very common. I had ago at pulling one injector plug off at a time to see if I could hear it but no luck. Autozone can't check them - no baseline ohms. i cannot hear anything under load or. I have a misfire at idle and low load/low RPM. I got it cheap knowing it had a misfire, and as I dont get my license back for 8 weeks, something to work on in the mean. The only issues I've ever had was a bad wiper switch and brake light switch that would turn the brake lights on when it got cold over night. completely unpredictable. When that occurs, the miss goes away so it's only under load at lower RPM. It would also run like absolute crap all the time, not just under load, if plugs were fouled. The repair shop had diagnosed the coil pack as faulty and fitted a new unit with plugs, but this made no difference to the problem. P0302 Cylinder #2 Misfire. P0351 means a misfire on cylinder #1. misfire under light load IGOTACUMMINS is an online forum and community for all Cummins Turbo Diesel enthusiasts. should give a flashing eml and show up on code reader, even the most basic ones should give a cylinder misfire number. Finally, one day while driving to work, it misfired and the check engine light. Midget 1500/Weber Carb Runs great at all RPM in shop. If no codes are present then I'd. Same thing happened to me a few months back (sputtering/misfiring under load). All in which came back ok/no codes. CYLINDER CONTRIBUTION Other Misfire Diagnostic Methods Other Misfire Diagnostic Methods The example below shows the upstream and downstream O 2 sensors for both banks of a Ford application with a V6 engine. The 94/44 code is gone, now its throwing a 42/92, so i replaced the o2 sensors cause they appeared to be the stock units with 152,000 miles on them no bueno. I have no smoke out the back or oil in the intake. 1999 F250 with a 2002 T444E motor. I had a mechanic that works for a GM dealership to look at it. 7 Vortec with a misfire, P0300 code for 3 months. Re: Misfire under load Kez, if you enlarge the pics the plugs are all the right type, the 'gap' on plug 2 looks massive! also if you enlarge the coil pack pic you can see the water ingress on two of the coils - my money is on water/fluid getting in. Exterior; Autolamp automatic on/off headlamps; King Ranch F-150 fender badge; Vinyl upper door trim panels w/integral armrest, front/rear map pockets, courtesy lights; Heating, Ve. The car now idles fine but misfires under load. The only mods done is a pod filter, FMIC, bigger fuel pump ( unknown brand or type), 3 inch from the dump and a manual boos controller which is wound right down to stock boost. we have it all installed and running. It will accelerate ok but power seems off. The code will not. Unfortunately, each time the vehicle was investigated and fault codes cleared, no problem could be found with the usual suspects (oxygen sensors, knock sensor, etc). 6 and a 5 speed. CEL lights and goes out at start up and is not throwing a code. FWIW, my '94 developed a small misfire around 60K miles when under light load or when starting from a stop. I had the misfire of cylinder #1 code and they ended up replacing my head after several weeks of diagnosis. 6 misfire under load - im working on a 98 ford f 150 with 215000 miles. I'm getting the cylinder 1 misfire, cylinder 2 misfire, and multiple/random misfire codes. So - i guess i only get the misfire towing a really heavy load. 42 lbs injectors, t44 turbo 3 in dp. Tried everything under the sun to get rid of it. It's the worst when going up a hill, I have to make it shift out of OD and hit about 3k rpms so it doesn't misfire. Cylinder specific misfire under load is typically a secondary ignition problem I would triple check plugs and wires and maybe even swap the cap once more before moving away from secondary ignition. After about 15 mins she showed up and said her bike would not stay running. Alice, Bob and Charlie are chatting together, and Charlie viciously launches an insult at Bob; but Bob, Master of Missing the Point, fires back, "I won't let you insult Alice like that!" Occasionally this will take an alternate form where. One or more misfire codes will be stored in the car or mini-van's computer memory (if OBD II equipped). I have no smoke out the back or oil in the intake. I'm getting a misfire code on cylinder 2. There is also no oil on the plugs. It developed a serious misfire with a Flashing Check Engine Light. What's New 3 12 24 72. I'm trying to help determine if it's definitely misfire or transmission concerns like torque converter. here is what I have established. com forums, you must first register. Injector pulse width will be longer than expected (significantly longer than 2. Truck runs great otherwise. CYLINDER CONTRIBUTION Other Misfire Diagnostic Methods Ignition Misfire Downstream O 2 Example The example below shows the upstream and downstream O 2 sensors for both banks of a Ford application with a V6 engine. When that occurs, the miss goes away so it's only under load at lower RPM. Ran fine at idle but under load would misfire. I had it Scan and there is no code also, nothing showed on the cylinder misfire calendar. Now the misfire is not just at idle, but mostly under high load partial throttle conditions while cruising. How to Understand and Diagnose Misfires. it does not show "check engine" lite or set a code. If no leak is found the next step is to replace the spark plugs. Now it runs as good or better than the the day i bought it. third problem - is engine seems to vibrate more than I recall the A2 did, misfire? fourth problem - is under load (on cruise going up anything more than a slight gradient) it starts to hesitate/surge and this is accompanied with a lot of smoke (unburnt fuel) if you then floor the throttle the surging/hesitation goes away but again low on power. The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. If you accelerate quickly it is not noticed, but makes a sort of a howling sound. try swapping plugs and wires from 4 and 6. 7L - P0304 cylinder misfire This is the first time for me to use any forum for help; but as I have been reading they seem very helpful. Typically an engine misfire under load, will be a problem with the ignition system, while low engine speed problems will be a vacuum, fuel management or compression issue. engine misses whem under load: Sign In Most time bad gas would cause a misfire the pcm would detect that and stored as a trouble code. The funny thing is - the car would do fine if I drove for a while. Note: Be aware that the #1 cylinder misfire code is a catch all. CEL lights and goes out at start up and is not throwing a code. We have a 2002 Buick LeSabre Limited 3. 04 Jetta GLI Catless Turboback exhaust Neuspeed Tune Intake AWE Diverter I picked up a GLi which seemed to run pretty well on the test drive. Replaced it and it was fine. Finally, what is that little box behind the air cleaner. The Mystery of the Misfiring MINI. From Day one The Truck seems to have a misfire but Not bad but noticable. 4 misfire with no codes detected I changed them also with some refurbished injectors off ebay for under $150. It only does it once it's at operating temp too. history, the original owner tried his best to pass on information. The problem has been on going for a couple months now. 7 Vortec with a misfire, P0300 code for 3 months. It only does this under load (heavy acceleration, accelerating up hill). Midget 1500/Weber Carb Runs great at all RPM in shop. The truck will not really misfire on idle, when you put a heavy load on it, (punching it from say take off) it will misfire hardcore, and start to shudder. Already replaced wires and plugs. is no misfire (See the confirmation driving pattern). I back probe #6 injector and got signal from ECM when under load in gear and above 1900 RPM when i. they are a no no in turbo pt's the heat actually destroys the plugs, I tried the platinums in my gt and when my car misfired badly, i pulled the plugs and found out the hard way. 1988 mustang GT Rough idle and misfire under load code 44/94 I'm having an issue that started about 3 weeks ago. Recently we completed a round trip from Dallas to Des Moines and back, and after the last fill-up in Oklahoma the car developed what feels like a misfire condition. My software could probably do it but I'd have to know the actual HEX command to send via the console as there is no "click and do" option to perform it. Anytime the CEL lights, a code is supposed to be stored in memory, even if the CEL goes off afterward (the code should be retained for 40 (or is it 80?) warm-up cycles, then will be purged if the fault has not occurred again). Could also be a bad spark but without a code it is hard to say. I bought a ELM327 wireless adapter for my iPad ($30 generic brand off ebay) and downloaded DashCommandthis allowed me to read and clear the car's codes and confirmed my suspicions that it was a misfire (Codes: P0300 to P0306). Put new boots all the way around and no more misfire and that tick is gone. We have a 2002 Buick LeSabre Limited 3. When this was completed, the car ran smooth and MAF output under load came up to 110 g/s. From then on the car will misfire and hesitate under load until I let it cool. They seem to occur for no apparent reason. It runs fine under load but I can feel an obvious misfire when idling and it stumbles around 1800 RPM with 1/8 throttle input and under. Hint: The misfire rpm and misfire load indicate the vehicle conditions under which the misfire occurred. Let's turn the page and we'll take a look at what you'll need to do to pinpoint and resolve the issue causing the misfire. 1999 Yukon - Finally fixed misfire under load at 70 mph Yukon Car Forums as no code it set but it is showing yellow on imissions. I've replaced the spark plugs with ne. P1298 Electrical Load Detector Circuit High Voltage P1300 Random Misfire P1301 Cylinder 1 Misfire - Compare possible causes/symptoms for this Honda check engine light code to the Generic OBD II code P0301 P1302 Cylinder 2 Misfire - Compare possible causes/symptoms for this Honda check engine light code to the Generic OBD II code P0302. No missed at idle in gear or in P with 3000+ RPM. Select the following menu items: diagnosis / enhanced obd ii / data list / misfire / misfire rpm and misfire load. Truck is misfiring only when driving with a load. Well hear i am AGAIN !! Im telling you guys this boat has been nothing BUT issues !! So, finally got out on the lake last weekend. I got a 99 tahoe 5. cylinder misfire, is present, this article does not apply. I am unsure as to the possibility of stored codes on this one if the light has never come on. literally like no power under load I cant speed up hardly to get around someone now. I just drove a 160 mile trip with my car on Sunday, and it ran normally (slight hesitation due to a bad CCV). 7L - P0304 cylinder misfire This is the first time for me to use any forum for help; but as I have been reading they seem very helpful. 6L Misfire, Rough Idle, Code Misfire #3. I have read a few more threads on this and I think that all I need to do is adjust the screws so that idle speed is about 1100 rpm AND the bodies are in synch. Check for any signs of wear and heat damage in all of the components of Ignition System. The code also may be erased if no misfires are encountered under similar driving conditions during the next 40 drive cycles. "Misfire" on a diesel - possible cause? It can't just be replaced without a diagnostic machine to re enter the C2I codes. Age of leads is unknown, I did try ones of my C20LET and there was no difference. I'm going to do a datalog under load to try to capture what is going on during the event and then send it to Tony at TIC and go from there. Rough Idle causing a Misfire Condition Case Study. Always carry a nipple wrench. This time it did not set a code. If you accelerate quickly it is not noticed, but makes a sort of a howling sound. Its starts very easily, but it now stalls under any load, whereas when the problem 1st started, it would only misfire under heavy load-acceleration/WOT. ive been noticing that sometimes (only noticed on highway) that my car misfires occasionally. New plugs, coils, fuel pump, filter in the last year All motorcraft parts except pump and filter. Odd thing is I'm getting NO codes at all (wish it would throw something so I could check). An engine that hesitates, stumbles or misfires when accelerating or when it is under load, is an engine that is either sucking too much air, not getting enough fuel, or misfiring. Re: Hesitation / Misfire / Bucking at highway speeds - no codes When a google search turns up dozens of threads on the topic, at different websites, with GM personnel participation in the forums, there is no excuse for a service writer to NOT know what the heck is going on. 5 liter V6 EcoBoost engine) without needing to block the intercooler, allowing it to continue running at full efficiency. Power is provided to the coils on the white/violet wire. I need some advise. Can unplug the #1 coil at idle and off idle with no change. There also were not any history or current misfires in the misfire data list. Weakening fuel pump - the engine may idle with or without misfires, but will misfire at higher RPM, under acceleration, or under load. I'm going to take the upper plenum off since there are only two blots left and the upper gasket set includes it, but I'm going to wait until I hear something on the lower. Misfire? Vibration under light load - I have a 1997 Ram 1500 w/ 5. If your "Check Engine" light diagnosis shows a generic cylinder misfire code, you should start with the most likely culprits first. Still misfiring under load/acceleration and getting worse. I suspect there may be a base engine concern, but I have never seen such a problem with V10's. 7 vortec with multiple misfires under load/accelerating. Misfire under load indicates one of the followings:-bad spark (weak coils or spark)-insufficient fuel pressure. I changed all the coils and put in Honda plugs. The problem is a consistent misfire at idle or when the rev is increased under NO load. I removed the plugs and cleaned them up about 2 months ago and it seemed to noticably improve for a few days before going back to as it is. anyone have. ive been noticing that sometimes (only noticed on highway) that my car misfires occasionally.