I have a stock 2000 GTP and when i put the pedal to the floor my car seems to chug like its shifting up aqnd down between gears and than my check engine soon light flashes at me. i replcaced all the spark plug wires on it last year. and than one day me and a friend got bored so we put some holes in the exhaust(really dumb idea i know. ill here about it im sure). But i just wanted to know if anybody knows what it might be. if it might be that im not getting enough back pressure for the motor or what. i also havent changed the oil for the supercharger at all. maybe that might have something to do with it?? anything would be helpful. thanks