as some of u might of followed a post i put up last week on a c5 i bought well i got it all figured out with the help of bill c thanks bill,as i have been driving the car i noticed it skiping but no cel light,so i put the scan tool on and i see that alot of the cylinders are missifireing once in a while i notice it most when if u punch it and then slow down ,i pulled a plug out and it is a ngk and it looked ok but who knows,the wires apear to be stock,but i am guessing that wires and plugs arew the onlt thing thAT WOULd do this any help guys thanks .