My car misfires but only during acceleration. Its suttle in the city but highway it reallly misses. Had it checked with a scan tool and it just says "random cylinder misfire?" It can't be plugs and wires they were recently changed and it can't be the coil pack because it only misfires sometimes? I don't want to spend 70 bucks if I have the answer. If it is where are they located (in an easy reach location I hope)

 

What kind of plugs?

 

It could be a faulty coil pack or the ignition module going a little under the weather. However, the symptoms you listed are synonymous with that of faulty plug wires. Granted they were recently changed, I had the same problem. I put a new set of wires on (and trust me, I bought the cheapest ones I could) and no more than a few months later, the problem was back. I gave in and bought a great set of AC Delcos and have had no problems since.

 

The spark plugs and wires.

 

I think thats what i replaced the wires with (AC Delco) It helped but it still did the same day.

 

If your ignition stuff is good, especially the ignition module under the coils,then the other likely cause of "random misfire" is a lean fuel mixture, change the fuel filter & clean theinjectors. The PCM does not look at the O2 sensors at WOT, so I doubt they are causing your problem, but you can always look at the O2 sensor activity with a scanner. If the output goes up & down continuously at fastrate they are good. I also suggest you use the OEM AC Delco plugs.

 

Thanks i'll try that. Im going to try to change usinga hanes guide so if you have any tips that'll be appreciated

 

One place you want to look is the towers on the coil packs. I found a rather large amount of rust on a couple of mine (from the coil terminals). Easiest to check and clean if you remove the coils. It's also a good idea to use some dielectric grease on the plugs and coil packs to help preventarc over and keep moisture out. And don't forget to treat the coil pack connections too.

 

I would also make sure the coil pack terminals are clean, and always use dielectric grease when they're cleaned...

 

thanks for all the feedback. try to get to it this week.