I noticed that you listed your spark plugs as double platinum. I'd yank those out. For boosted cars you want copper core plugs. Go for Autolite 605's for a stock car. Also if you want to pep her up any in the future read this thread.
http://www.grandprixforums.net/f81/s...car-17482.html
It also has a lot of useful knowledge about our car.