Spark Plug Issue
 

OK, my 91 GTA was idleing a little rough and I noticed the last time I was driving it that I didn't hear the fans coming on. So I brought the car to GM and they fixed the fans (some faulty switch) and they are telling me that my rough idle is being caused by my spark plugs.

Per the recommendations on this board, I went with standard AC Delco Plugs. They are telling me that they pulled 2 plugs and both of them were gapped at about .010. I know for a fact that I gapped them at .035. Is it possible that the gap changed or are they blowing smoke up my a$$? They wanted $250 to pull the plugs and re-gap them so I politely thanked them for helping me and requested they put the car back together.

What do you guys think?

BTW, aside from the car idleing rough, it runs like a top throughout the rpm range.

I've heard people claim that carbon build up could close the gap setting on plugs, however I don't know how true that is.

I've heard that as well. These plugs have less than 1,000 miles on them so I don't know if that would cause it.

In addition, this engine is bone stock.

just regap them and everythings good :-)

its time you learned to changed the plugs its not hard its just a simple take your time and only do one at a time take off the boot ( plug wire on plug ) screw it out and than the new one with what ever the gap is to be .035 / .060 whatever try to do the ones you can see real easy first with the motor cold -- jz

I pulled all the plugs and regapped them. Amazingly, they were all at about .10 when I know I gapped them at .35. In any case, the car runs perfect now. The only plug that gave me a hardtime was the 3rd plug (going towards the firewall) on the driver side but I got it.

i bet it felt good when it worked -- jz