My own diagnosis of a misfire...

[INF3RN0666]

I've been having an idling misfire (disappears at high RPM) in Cylinder 2 for a long time, as some of you might recall. Had my mechanic look at it a while back and do a lot of diagnostics. As my most trusted mechanic, he says it's a valve, lifters, or rockers problem. Financially, I can't accept that LOL. Just to check his work, I've been slowly testing components. We have ruled out injectors, coils, plugs, wires, EGR, MAF, & MAP so far.

Today, I read that the injector driver could fail, and that's found inside the ECU (PCM, ECM or whatever it is). So I did the best thing I could given my equipment and tested for voltage when the ignition is on (but not started). All the other cylinders would indicate a voltage of 3.3 and rise upto 9 volts, except for cylinder 2! BINGO!!!??????? Cylinder 2's voltage stops at around 6 volts. I have no idea what that means. Does it prove that the injector driver is failing? What is your take on this? Should I go buy an ECM from a junkyard and test it?

Thanks for taking the time to read and help out.

[UncleBob]

what are you measuring it with?

The simplist answer is swap the injector with any other cylinder and see if hte problem moves

[INF3RN0666]

Already tried that man, it doesn't move. Injectors are all fine. Using a multimeter, I was testing the voltage coming from the ECM to each injector. The voltage from cylinders 1,3,4,5,6 will read 3.3V at first, then rise to 9V after 3 seconds. The wire for injector two reads 3.3V at first, but only goes up to about 5.5V. Does that indicate that I have a problem with my ECM?

[UncleBob]

what instrument are you using to measure the voltage?

If you've ruled out everything but the computer, then you've answered your own question: replace ECM

[INF3RN0666]

I'm using a multimeter to measure voltage off the wires coming from the ECM. The thing is, I haven't ruled out bad valves, lifters, or rockers. I just don't have $1000 for all those. ECM would be a cheaper fix.

[pbaddict03120]

go to a junkyard and get an PCM it will work for about 20 dollars

[INF3RN0666]

Originally Posted by pbaddict03120

go to a junkyard and get an PCM it will work for about 20 dollars

Hey man, that was my thought exactly. My only problem is that some places say "Module must be programmed at dealership to insure driveability & emission standards". I thought a used one would already be programmed.