I bought a GSL-SE and gave it a tune up last week to see if I could get rid of the back firing it has. After changing the plugs, wires, distribitor cap and rotor, its still back firing, but after it warms up it goes away. Can anybody tell what thats all about??? Thanks for your help!

 

I'd start with checking for exhaust leaks. After that, check all of the cold start related systems in the FSM.

 

Check the vacuum too.....

 

Thanks guys I will start doing that and do appreciate the feed! When I find out what it is I will fill you in.

 

Don't drive it when the motor isn't warm