I have a 97 Cavalier 2.2 with 70,000 miles on it and just about a month ago it would give me a very rough idle when i would start it after sitting about a day. I just got a brand new set of AC Delco platinum series plugs put on along with new plug wires. i dont know why it is doing this now my guess is i got a bad set of plugs wires cause it never did this prior to the new plugs and plug wires!