Hi, my 97 Bonne SE (non */C) w/ 115k keeps throwing a random/multiple misfire and a misfire on cylinder # 3 code (two different codes). Only feels rough at idle and the exaust pops...like 3 or 4 times repeatedly then pauses and keeps doing the same thing over and over. I can really feel the vibrations in the steering when im idleing. Changed plugs and wires when problem first started, problem is still there although the car did need the plugs. Also checked intake manifold for vaccuum leak and couldnt find any. IAC valve just replaced and MAF sensor as well. Does this sound exaust related as the noise is coming from back there ?

how old are your plugs, wires and coils???

Plugs and wires are about 3 months old.....plugs i used are Autolite platinum. The coils have never been replaced to my knowledge.

Your coils probably need to be replaced.

Yep, had that same code on my '97 SSEi.
Change the coils.......all of them.

With just a misfire code..there is no reason to just replace parts to spend money. Swapping the coils, checking battery cables for corrosion and connection, and connection of ICM is the first steps I'd recommend.

Simply replacing all coils is typically a waste of money. One coil may fail..but two at the same time? Doubtful.

If the ICM fails..ok..it might act like more than one coil. If you need coils or ICM'* please check the for sale section or pm me.

okay...forgot to add that a mechanic that checked it out earlier did swap my coil for cylinder 3 with a good one and there was no change. Could the other coils cause a problem then ? Also is there a lifespan for coils as there is for spark plugs ? I will try to swap them and see if that changes before i spend more $.

do you have a multimeter you can check the resistance? this sometimes can help rule stuff out.....if one coil is really bad it will show up on a multimeter.

It could be ICM related or crank sensor or anything related to the ignition process.

Update: check engine light went out yesterday and hasnt come back on since.....but misfire is still occuring.......any thoughts ? And yes i can get ahold of my dads multimeter to check coil resistence. Could a misfire be caused by the EGR valve ? i read somewhere that it could have trouble opening or simply be stuck. Also ill see if swapping the coils around with help me narrow the problem even further.

get that code scanned, even tho the light is off the code can still be stored in the PCM.....that will tell us somemore info on what is going on