ok so i have an 06 s/c and its been running like **** lately. sounds like it has a misfire so i changed the plugs. its definitely losing power bc when i first bought the car i went to the track and ran 14.3...now im running in the 15's and idk why. im about to replace the catalytic converter(took it out bc it kept clogging up). car is running really rich from what my friends are telling me...any ideas on how to get my car to run correctly??