Did the compression test, here are the results (cold engine btw):
Cylinder #1 dry 130, wet 110
Cylinder #2 dry 110, wet 113
Cylinder #3 dry 130, wet 126
Cylinder #4 dry 107, wet 103
I'm wondering why the driver's side is lower than the passenger's one.
Also checked for vacuum leaks with carb cleaner, found none. Test drove the car, no CEL and it drove great. This morning I let the cold car idle in the garage and monitored the misfires with Rom Raider. For a minute there were none at all and I was getting hopeful, but then the count on #4 just shot up and the CEL came on eventually. See attached image for graph on the misfire count over time and engine speed.
Also, there are some misfires on all of the other cylinders from time to time, but no more than one or two before the counter resets.
So, I'm wondering the following:
- Why did the misfires show up only after a minute or so and not right away? What changed within that one minute that could trigger them?
- If everything were normal in the other cylinders, the misfire count there should be zero, right?
- Can one or two misfires be dismissed?
- Can it still be the fuel injectors if I'm seeing misfires in pretty much all cylinders? Maybe we need to look at the bigger picture?
Thanks for the advice, StkmltS, I will check your post. For now my suspicions lie with fuel delivery since I already excluded ignition and combustion air.