Atomic

iTrader: (42)

...anyone?

fossil

iTrader: (1)

I would try swapping the injector from another cylinder, if still missing I would
look at my fuel trim numbers when missing to to see if you have positive numbers, plenum gasket bad about leaking (worse on cold start ups). I have seen the ground bad for the coils on a few trucks. If still missing I would disconnect exhaust pipe before converters and run and check.

When diag any miss I always watch my fuel trim numbers and MAP sensor readings very close when vehicle is missing it helps guide me to proper diag.

Gordy M

iTrader: (2)

You might try an injector balance test, it would go something like this:

Run you logging software and unplug one injector at a time and wait until the maximum LTFT change is reached. With one fuel injector unplugged, the oxygen sensor will see a lean condition and the PCM will compensate by increasing the pulse width of the functioning injectors to reach stoichiometry (14.7)

The results of this test MAY look like this; with injector No. 1 unplugged the LTFT change is approximately + 14%, injector 2 +10%, injector 3 +17% and injector 4 +16%. Injectors 3 and 4 contribute a greater volume of fuel than injectors 1 and 2. We know this because the amount of fuel trim increase is greater with these injectors unplugged.

Injector 2 is the cause for concern; with injector 2 unplugged, the remaining injectors need to supply only +10% total. While this is an oversimplification, it will help you isolate whether an injector is the culprit.

Atomic

iTrader: (42)

I am still having this issue. The check engine light will come on ever couple of days with the same p0300 (engine misfire) code. The engine sounds fine and runs great.

Here is a hpt log if anyone wants to look. Its 90% on cylinder 2, but only at idle or coasting.

Are there any other ideas besides pulling injectors?

budhayes3

iTrader: (19)

Is the engine actually misfiring? Can you feel it at idle? Maybe it's a tuning thing...I was getting false misfire codes after my cam swap until my tuner softened up the misfire monitors

Atomic

iTrader: (42)

I dont think it is. I dont hear or feel anything I can interpret as a misfire. I havent changed anything since april when I put my cam and springs in, it just started doing this when the weather got cold.

budhayes3

iTrader: (19)

Do you think maybe it's just a false misfire that you can tune out?

Atomic

iTrader: (42)

I initially lowered the sensor sensitivity when I put my cam in. Why would this pop up now though and not 8 months ago when I put the cam in?