my car has had an ignition problem for a little while now.......


it started dropping a cylinder at idle, so i changed the plugs and plug wires, and i have fairly new coils on it (97 4.6 2 valve)


so i changed all that and i still have the problem, it throws a check engine light so i pull the codes.....


it says it it detecting a miss in cylinder # 2 ... so i look it all over and everything seems fine.... plug is burning clean and all........



now, it only does this at idle........ so i am trying to figure it out......


i thought it could be something mechanical (leaking/cracked valve) at first but the computer is detecting it, so that means it is not mechanical........


anyone have a clue what it might be?????


the computer also threw some weird emmisions code, that the guy didnt know (autozone though) but i think the emmisoins code is from the rich condition of the cylinder not firing at idle..........



anyone here good with ignition and or OBDII computers......

i would really like to figure it out without spending 100 bux to put it on the ford diagnostic machine..............




any help is appreciated !

 

can you swap the coils around and see if the problem follows the coil? (don't know much about mod motor ignition, but would be an easy way to isolate the problem).

 

thought about trying that ,

i'm almost certain that if the coil was bad it would drop all 4 cylinders, not just the 1 .........


and as i said, it only does it at idle............ once you give it some gas it is fine.............. so????????

 

possible arcing off of a plug wire?
other than that possibly an issue with the injector or how the computer is seeing the injector? pulse width screwing up?
Throwing stuff against the wall, seeing what sticks..

 

plug wires are brand new motorsport wires......... with no signs of breakage........



and as far as the injector, i thought of that....... but how should i test them???? i know there is a way to do it by checking the ohms, but what should i look for? the electrical or mechanical side of the injectors???

 

ps, wouldnt the computer just say the injector has gone bad as well??????

 

honestly don't know man.. you would think, but maybe since it's intermittent it won't just say "hey #2 injector is bad".
I'd lean towards electrical, but check both if possible. as to how, well that's over my head (Sorry)..

 

Disclaimer - I don't know crap about mod motors. That said...

Are the wires exchangeable side to side? Start swapping one component at a time. Wire, then plug, then coil, then injector.

If a plug on the injector was somehow cracked, could it short out. Not sure why it would do it at idle only, but you never know.

What about a vacuum leak causing a miss?

 

Considering the you just changed the plugs and wires I'd swap an injector and run it on the computer again. Last resort swap the coils, see if the Cylinder # is the same.


...or you could drop a B16 in, and never have any problems