GMC - Sierra :: 2004 - Code P0300 Random Misfire While Under Load
Apr 12, 2016
2004 GMC Sierra 2500 HD, 227,000 miles 6.0L V8.
While driving up hills or increasing load, the CEL will flash multiple times, I pull over as I know CEL flashing is not good. 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. Truck has poor MPGS, idles rough, loss of power. this happens every time I drive this vehicle as I use this truck to pull my trailer that weighs around 4000 lbs. Problems come and go. Some days I can drive the truck for an hour with no problems, come up to a red-light, BAM, CEL is flashing, truck is bouncing side to side due to the poor idle, other days this happens while sitting in the parking lot of my job with the ac on.
Truck has been to the shop several times as I'm no mechanic. Parts replaced are as follows:
- Fuel pump
- Throttle Body
- All plugs
- All wires-All Coils
- Intake Manifold Gasket-
- Battery
- Sensor 1 Bank 1 O2 Sensor
- Sensor 1 Bank 2 O2 sensor
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I have a 2004 Hyundai Santa Fe 3.5L V6 when i was driving a couple of days ago the check engine light flashed and after a while it stayed on the codes are P0300 which is a random misfire as well as a misfire in cylinder 2, 4 and 6
I replaced all 6 spark plugs and the 3 spark plug wires still the same issue. The car hesitates when accelerating when i accelerate it looks like it wants to stop the rpm goes to almost zero and then it moves and so on. the rpm goes up and down like crazy.
Sometimes it won't move past 1000 rpm I'm moving 60mph and still on 1000rpm and sometimes it works just fine like there is no issue at all. When idle the car is fine and everything seems normal it stays on 900rpm. The car has 158K miles on it.
I uploaded a video to show you what's happening to the tachometer when I accelerate [URL] ....
I'm on a limited budget I'm thinking of changing the ignition coils but i want to make sure that's what is causing the problem first because i spent 200$ to change spark plugs and wires and the mechanic didn't fix the issue.
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'02 TB w/ code P0300 / Random misfire. Started the other day when it was very damp out, FWIW. Feels like ur driving on rumble strips during acceleration. Rough idle also. It does not do this continually though as after a while (minute) it clears up and runs smooth for a while then runs rough & light will again for a while. I seafoamed it today since it been about 60k since last seafoam. I thought that might have worked until I drove about 20 mile and it went rough again. I also cleaned the oil out of the cam sensor elect connector, since that caused rough running before, although it didn't throw that code. It seems to be very intermittent. '02 TB, 185k miles, orig plugs changed at 125k. Is it actually just going in & out of a limp-mode? O2 since it's random ???
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Recently i started the car and it was shaking more that usual. the CEL light came stating P0300 with random misfires. It sounds and feels like misfires so i believe this is true.
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I have a 2000 Impala with a 3800 V6 series 2 with 165,000 miles. The only code I had was a P0300 Multiple random misfire that occured off and on at first, Worse in the city Better on Highway. It would start running on half the cylinders and bogged down, with the check engine light flashing, after getting onto the highway it would straighten itself out at first. I thought i had water in the gas so i ran some heat through it. straightened out for a day then happened again so I thought maybe a should run some premium gas in it, The car ran like total crap until the premium was gone, so i thought maybe it's running too rich, I put 87octane in it and it ran great for a day or two, then it gradually got worse to where it would not straighten up on the highway, tried to die at stoplights and i had to drive it with 2 feet to get it home and park it. I've replaced the battery, spark plugs, wires, ICM checked good, coil packs are good, replaced fuel Pressure regulator, looked for arcing on the spark plug heat shields and it will not start. It turns over but doesn't try to ignite and when I get the slightest rumble of ignition, it backfires up through the manifold and I see a puff of gas or light smoke by the exhaust manifold.
The car had a vacuum leak around the intake manifold cover gasket and a leak on the fuel rail. I pulled the fuel rail off my impala, snugged up the rest of the intake bolts then disassembled the fuel rail, flushed it out and cleaned the injectors the best i could, then reassembled it. before i re-installed the fuel rail I hooked it up to the fuel lines outside of the engine and tried to start the vehicle. all injectors had a nice spray pattern. So i installed the rail and it still didn't start but it had more combustion than before although it's still backfiring like before. Checked the fuel pressure by turning the key on and the fuel pressure went to zero very fast. I blew the rail out with air so to make sure i didn't damage the regulator I replaced it with the old one, ran the test again with same results, so i reinstalled the new regulator. I performed the fuel pressure test a few more times while moving the fuel hoses and when i moved the back supply line the vacuum loss stopped then dropped to zero when i let off of it. So I replaced the fuel line connector and O-rings on the injectors. It no longer has a vacuum leak.
I cleaned the EGR Valve out and had no luck there, then I removed the Idle Air Control Valve-pushed the pintle in, re-ionstalled it and WooHoo! it started! Although it still ran like crap with the same random misfire I was still happy to hear it start.I pulled the plugs on it to do a compression test and all 6 cylinders have between 180-190psi so the engine is in good condition mechanically. I installed new plugs before getting the car restarted and when i removed them for the test they were covered in thick black soot after running for roughly 15 minutes max.
I have (2) 2000 Chevy Impala's so I've swapped sensors from my wifes car to see if it would fix it. I've tested the following MAP, MAF, IAC, coil packs and ECM. None of these made the car change. I believe it is a timing chain because the car has never had a new timing chain and is way overdue, but I haven't had a code for a crankshaft position sensor. Can the timing chain be bad without throwing a code? It's not out of time enough to change the valve timing because I had a good compression test but its not firing right and still has the multiple random misfire. I have not checked or received a trouble code for o2 sensors, crankshaft position sensor or cam sensor. Something has the timing retarded and is dumping extra fuel into the engine because my new plugs looked like they were in the engine for a year.
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I have a 2007 Hyundai Accent GLS. I just got it from a used car dealership (local) and it runs perfectly. It had a misfire code when i first got it, for all cylinders plus the p0300. It went away when i started the engine again, and didnt come back til a month later (Now). now it wont go away.
I went to advance auto and had them use their OBD2 reader for a trouble code and i got p0300, p0301, p0303, p0304. No other codes present.
I am not feeling anything bad, and from what I am told, a misfire feels like a hard shift. This is of course after getting the plugs and wires changes as well as an oil change. Standard preventative maintenance.
The mechanic used OEM parts got from local parts shop. i think the OEM plugs are the copper ones. I would have preferred iridium as they arent that much more expensive but I don't want to pay for another plug change.
The only symptoms I can think of, is that according to google, I should get around 380 miles to a full tank (11.9 capacity, 32 mpg city). I am only getting 280 from full tank to gas light.
I have also gone through a lot of oil. I checked the dipstick and it was below the low line, so i bought a quart of high mileage oil (same exact brand and type of oil that i gave to the mechanic to use) and it went to just above the full line. This was at around 1500 miles after oil change.
After visiting multiple sites about misfires, i found a few things that caught my attention. One is a site called auto service professional, which talks about the OCV for the MC accent. A lot of sites also recommend gaping the plugs at .035.
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My 03 Chev Avalanche is giving me a P0300 code (multiple or random misfire). With no distributor or individual coil is this something I can fix myself or is it shop time?
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Had this code show up after the warning light came on and then the light went away after two day, the car seems to be a little sluggish now. I have read that this is a random engine misfire and it could be a bad plug..
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I know it is a random cylinder misfire code however I started my car in the morning and it was fine I moved it and put it back in my driveway. I started it up later and waited for it to heat up i came back outside 10 min later and my check engine light was flashing and my car was shaking like crazy you could tell the engine was misfiring like crazy. I had under a quarter of a tank but not empty yet. I shut it off and turned it back on and it was still doing it. I drove the mile to the gas station the way it was.
Under partial throttle it was revving to 4500 and over 5, had to let of throttle to make the car shift up a gear. I filled up and started the car again performed fine after that however the check engine light was solid now and still on. I went to my local mechanic and he read that code P0300. I changed my spark plugs that day and they were crap the original spark plugs I have 65,xxx on my car now. Car is smooth now. I cleared check engine when i saw him first and it did not come back on all day even before i changed the spark plugs later that night. Why my light was flashing and why my car was acting like that till i filled up?
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Just started getting a p0300 random misfire code on the durango a couple days ago. pretty sure it isn't moisture related since it started on a nice sunny day. it was running pretty rough so it was obvious that it was misfiring. I changed the plugs since it was about time anyway, and they needed it and I cleared the codes. new plugs (put in the oem champion copper plugs) didn't make the problem go away. The engine still ran rough and the code came back. 2 of the plugs looked like they may have been fouling a little bit. they were a fair bit blacker than the rest of the plugs. I went ahead and changed the coils on those two cylinders and reset the codes again. Still runs rough and the p0300 came back. where do I go from here? I am not getting any specific cylinder codes so it makes sense to me that it isn't one or two cylinders not getting spark. 2003 durango 4.7 ....
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New plug on right, lower bank 2 plug on left
Started getting a P0300 and various misfire codes for random cylinders. Truck has 95,000 kilometers so figured I would change the plugs. Several of the plugs on the lower bank on both sides were pretty much toast. Most of the plugs on the top looked good. All of the plugs had a small deposit where the spark hits the ground probe. Picture is typical plug from lower side. changing the plugs should make a big difference in how she runs and eliminate the codes.
Took right on 4 hours same as dealer said it would. I would have got it quicker but it was not a race.
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I have a p0300 code coming up on the comp. The motor runs fine until it gets wet. rain/carwash. I have tried to spray each coil with water and could not get it to misfire. Then I brought out the water hose and sprayed it top of the motor this found the misfire. This thing has 8 coils and I really don't want to replace them all. My Question is there some thing else that could be causing the misfires.
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I hookup an OBD2 tester on my Prius 2014 Plugin and saw the OBD2 P0300 - Random Misfire. I did a reset and the error still came on. I also tested my friend Prius 2014 Plugin which is factory stock and had the same error. Wonder if that is by design or not. Going to take my ride into the dealer on Friday for my 25K maintenance and have them look into that error. P0300 can be anything. Hopefully doesn't cause more problems down the run..
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OK - so is my engine computer toast? The other day on the highway on the way home from work, my check engine light started to flash, and the car on cruise decelerated from 80MPH (ok I was speeding) to 70, and flooring it didn't make is speed up, and that's when i noticed it was shaking a little, so i pull off the highway and it's as if a spark plug was pulled.
So I made it to a parts store to have the code read, then started it back up, all was well. As if nothing ever happened. So I dismissed it as a pocket of water in the fuel or some other oddity.
2 days ago it happened again on the highway. So I pulled into the shoulder, shut off the car, and started it again. Runs fine. Engine computer?
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My 07 3.3 SF is throwing P0154 and P0300 codes. Autozone said the P0154 is Bank 2 pre-cat O2 sensor. But exactly which one? The P0300 is random misfire. Could they be related?
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The check engine light keeps coming on and off on my 2001 Echo with the above code. The car runs fine and the check engine light randomly comes and goes. What would set off the check engine light, but not cause noticeable change in performance?
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The "check engine" light on my 2004 Dodge Intrepid has been on (not blinking though) for months and, after putting new spark plugs, wires, ignition coils, 02 sensors, cam sensors and other things, the code that keeps coming up is P300 random misfire. After a few of the above items were put in (particularly the 02 sensors), the light would go off for a day or two but then always come back on. Because of this "random misfire", the car basically has no power when I push the accelerator down (at least until it warms up for a while and even then too sometimes).
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Friend has a 2006 with the 4.6 motor. From time to time he gets a random misfire code ( I think its 0316).. He claims it will only do it when the gas tank is less that half full. I don't see any correlation between fuel level and the code. I am going to check fuel trim values, etc, when the code is set, this weekend.... all I can assume is low fuel pressure which sets the code... Any problem with the pressure module or fuel pump / discharge hose that is related to low level in the tank ?
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I've got the intermittent misfire codes on my '02 Camry, and after changing the spark plugs and the ignition coils the problem still persists.
At first there was no noticeable misfire, I took it to two different mechanics and neither said they could find anything wrong. A few weeks later the misfire became noticeable when I'm sitting at a stop light. I can feel an occasional rumble in the engine.
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I took my 2006 W12 to get its yearly smog check, and it will not run "air" monitors due to intermittent misfire. The code is P0300.
Any way clearing this up? (I could find no air leaks)....
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I have a 2004 Jetta 1.8t 6speed, I recently bought it from a person(my first VW ever) so just trying to fix some things on it, One thing that I'm stuck at is My CEL, it keeps flashing the code P0501 and some random misfire on my cylinders, I have reset it and they keep coming back.
when I put about 10-15% throttle it revs up fine, no misfire or hesitation until the fuel gets cut off around 5500, which is 1k below factory red line, does not hit a thing like the rev limiter where it pegs off the top multiple times just fuel cuts off.
If i put anything above the said pressure the car then begins to misfire and lots of hesitation and that's what causes those codes to go off.
I've been reading many things pointing towards the engine speed sensor or the wiring. Occasionally my fuel/temp gauge quit working but I believe that is a separate issue all together.
So really trying to narrow down what is actually causing my engine to hesitate at low rpm.
Also i might note when I'm in neutral I can go wide open throttle and the car revs fine until the cutoff and only does the bog down when it's under full load. It sorta feels like the possible misfire is due to bad air/fuel but really do not know.
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