Alright guys I have been having a little bit of a missfire for awhile. More details can be seen here: https://www.evolutionm.net/forums/sh...d.php?t=339870 Anyways my car will miss at idle and if I hold it at different rpms it will miss even worse and throw the P0304 code. I have tried many different things and still haven't found the problem. So I took a 2 logs of it today. First one I start out letting it idle, then turn on the ac and rear defroster and headlights (which for some reason makes the idle good), turn all that off and hold it at different rpm's. That is when the P0304 code comes on. Second log it just letting it idle. I need to get this taken care of before I get tuned again, incase its something that warrants using the trusty warranty Please help me guys...I am stumped. Even the dealership hasn't pinpointed the problem.

 

Assuming your car is 100% stock right now.

Your fuel trims are really high, It means the ECU thinks your lean so it's adding fuel. Fuel trims should be closer to 100.

My car did the exact same thing but it was due to a malfunctioning/clogged injector.

Things that can cause the ECU to believe it's got a lean condition

Lean fuel mapping
Post MAF air leak (intake or exhaust)
leaky injector seal
malfunctioning injector
malfunctioning front o2 sensor

Since you've got a P0304 I would look at injector 4. What's confusing them is your car is probably running pig rich because the ECU is compensating for the condition and it's doing it globablly, eg not just richening cylinder 4.

I dont know much about the idle control valve on these cars but that sounds feasable as well. I just got done reading the responses on your other post.

Maybe some guru's will comment in.

 

post updated.

 

Well the only thing that is on my car right now is my exhaust, ams licp, and drop in. Stock tune is in currently. I also just had injector seals replaced last week. So I will do boost leak test today if it stops snowing

If the o2 sensor was going do you thing that would show in evoscan? Myself I have been leaning towards the injectors or something ignition related.

 

either your injectors have a fault or your latencies need help. since you just did something to the injectors ...
lots of miles? maybe they need cleaning

 

Car just turned 30k miles. Injector seals were replaced by the dealer last weekend. This problem though has been going on for almost 8 months. I have tried seamfoam through it hoping to clear up maybe dirty injectors with no help.

 

Switch you injectors around an see if the code follows to anothe cyl.

 

I just wanted to see if anybody has anybody else could look at the logs...specifically the 2nd one. I have narrowed my problem down to bad injectors, o2 sensor, or some type of vaccum leak. According to my logs does it look like the o2 sensor is doing its job? My fuel trims seem really messed up which indicates a bad injector to me.

I dont have time to switch around my injectors so I am hoping I can narrow it down to them and take it to the dealer. I appreciate the help guys. Need to get this figured out before I get retuned.

 

You forgot the most important and PITA thing that could make the car THINK it has a lean condition. Any misfire will make the O2 sensor read lean. There is a lot of things that could cause a misfire.

 

Markley02, It should be noted dbsears came to this thread to post logs to be reviewed, the orginal thread was posted in Engine/turbo/drivetrain. I've posted the link to his OP. Agreed, all kinds of things can cause misfire.

https://www.evolutionm.net/forums/sh...d.php?t=339870

Here is a indepth article on misfire diagnosis.

http://findarticles.com/p/articles/m...n17195225/pg_1

 

I had the p0304 code and for me changing injector locations to see if code move from cylinder 4 to another would tell me if I had a bad injector and ion the end simply swapping injector locations and insuring the injector seals were sealing properly solved my problem.

 

Just had this problem today on a car. He was getting P0300 random misfire. Had a leak on the intake pipe after the MAF. Plugged the nipple where the boost solenoid hose goes and problem went away.