View Full Version : Misfire codes P0300, P0301, P0302

11-20-2009, 01:56 PM
I am getting mulitple misfire codes (P0300), and misfire code for cylinder 1 and 2 (P0301, P0302).

I am able to get these codes to pop up whenever I want them to if I go past 50% throttle under load. Idling and revving the car with no load is no issue at all.

Stuff I have done so far:
Moved my coilpacks around alot,
changed sparkplugs,
compression test,
moved fuel injectors around,
no boost leaks,
no vacuum leaks,
cleaned MAF,
tested the diodes in the ICM,
checked fuel pressure,
swapped ecus.

And they keep coming back whenever I am under load and more than 50% throttle.

What do you guys think? p.s. Thanks in advance

11-30-2009, 02:43 PM

adr3naline fix
11-30-2009, 03:21 PM
If you let the car idle for 5 minutes (letting the car warm up) do the misfires start while sitting?

I would also swap a working ICM in there to rule that out - that is a very common problem.

11-30-2009, 03:23 PM
misfires only happen while in boost and more than 50% throttle..

I can rev my car up and down while in neutral all i want and there is no misfires.

As far as the ICM, I have done the diode check and it comes out fine.

12-01-2009, 07:01 AM
Have you swapped out all of the coilpacks for new ones?

12-01-2009, 07:36 AM
having same problem, switched out all the cp's (albeit off my last car), icm, spark plugs, coolant sensor.

im next gonna try the knock sensors and try to find a boost leak.