has anyone ever had a pcm go bad......are they expensive ???are they hard to install????do they come preprogramed???
what are the problems they create then they are broke???how do you test them??? sorry for all the questions but i'm maxed out on new ideas about my 97 4.2 that will not idle smoothly.
tommy m

 

I've been reading your other posts about the #2 misfire, lean condition and rough idle. I think you may have a bad injector.

If you're capable, you certainly could switch the #2 injector with another and see if the misfire code follows it to that cylinder. I think under the circumstances though, you may want to just bring the truck into a mechanic and have them test the injector. To replace: The injector is around $50.00 and a Ford dealer would charge 2.3 hours labor.

Considering as well that this is a high-mileage 1997 4.2L, you may want to rule out coolant leaking into the #2 cylinder and fouling the plug. Is your coolant level steady or does it drop?

 

the reason i'm unsure of the injector is that the code has changed from misfire on 1&3 cylinders to just the #2 cylinder now.

thanks tommy m.