Random misfire help
#1
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Random misfire help
I've been struggling with random misfire codes since 2009. I've performed the following to resolve it... but to no avail.
- Replaced spark plugs
- Valve adjustment
- New air filter
- MAP wack/reset
- Swapped ignition coils
- Compression test
- Leakdown test
- Techron fuel cleaner
I read this on another forum:
Can someone point me to some resources on how to troubleshoot a vacuum leak, a leaky EGR valve, and low fuel pressure? I can't seem to find any.
- Replaced spark plugs
- Valve adjustment
- New air filter
- MAP wack/reset
- Swapped ignition coils
- Compression test
- Leakdown test
- Techron fuel cleaner
I read this on another forum:
If you find a P0300 random misfire code, it means the misfire is random and is moving around from cylinder to cylinder. The cause here would likely be something that upsets the engine's air/fuel mixture, such as a major vacuum leak, a leaky EGR valve or unusually low fuel pressure (weak pump or faulty pressure regulator).
#3
Originally Posted by s2000maniac,Jan 19 2011, 05:03 PM
try cleaning your injectors first.
the problem usually occurs between 3-4k rpm. but sometimes i don't even get a flashing cel just a loud popping noise coming out of the exhaust. i don't think it's a bent valve coz it would happen pretty much all the time wouldn't it? btw, my idling is smooth no hiccups no misfires whatsoever.
could it be...
knock sensor?
fuel pump?
fuel injectors?
or what?
#4
i'm no professional but, if the vale(s) are bent or slightly the motor would have trouble with compression in lower rpms as you mentioned 3k-4k rpms seems low enough. low compression could cause misfire since there is not an efficient combustion. Although I could be 100% wrong here!
so try the compression and leak down test.
so try the compression and leak down test.
#6
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I doubt the problem is with the injectors. I swapped them around and the error code is always the same.
P0302
P0304
P0300
P1399
Besides the CEL being on, the car feels completely normal. There is a fuel smell which means it's running rich.
P0302
P0304
P0300
P1399
Besides the CEL being on, the car feels completely normal. There is a fuel smell which means it's running rich.
#7
i do feel the misfires and it's usually when the car is all warmed up. it doesn't misfire at all when idling or when accelerating. when i cruise at around 3-4k rpm that's when it misfires but not as much as before when i swapped out the coil packs. sounds something like an electrical problem to me but i can't yet to figure that out for sure. btw, i have no cel that's turned on at all, just flashing ones every now and then. thanks