Mrbrown

So I have been having a lot of missfire issues.
i have replaced all the plugs,coils,and injectoinjectors. I am still getting random missfires. Sometime when I scan it it will show a missfire for say 2 and 4 then I will reset the computer and it ok for a day or two sometime only good for a few hours. Then when It starts again I get it scanned and it will say I have a missfire on say 1,3 and 4 yesterday the cel starts to flash so I shut the car down for a few, started it back up cel off. Driving home it cam back on. So this morning it was reading a missfire in 1,2 and 3. Started thinking maybe head gasket no normal signs of a head gasket leak. But maybe?? Did a compression test with engine warm and the readings were. #4 155 ish, #3 155 ish, #2 90, #1 180. Thinking all but #1 are lowered than they should be of course 2 is not good at all. Will be doing a leak down test when the wife get back. Any thoughts. Could it be a bad ecm?? Head gasket??

Wankenstein

Redo the dry compression test and include a wet compression test. Follow these steps:

Charge battery a minum of 8 hours prior to compression tests. Charge battery during compression testing.
Perform at operating temp.
Go a few rotation past highest psi output to get accurate accurate reading.
After dry test repeat same test with two teaspoons of oil per cylinder.

Cylinders should be within 20% of each other but ideally 10%.

Mrbrown

So now it only shows a missfire on #2 this morning it was showing 4,3,2