If the car is backfiring, I would venture a guess that your timing is off. I know I asked you but I dont remember, has your timing belt ever been changed? How many miles on the car?

 

yupp i had to change the timing belt at around 103k miles i think bc i went to check the oil one day and looked and the timing belt was just two threads. and it has a little over 106k. and i think my head gaskets are starting to go bc it idles high until the temp gets to about 170 then the idle goes down to about 950 rpm. and the car starts shaking. gah this car annoys me sometimes lol. im starting to wish my grandmother would have told my grandpa that she liked the 99 gtp instead :O