I have a 98 trans am ls1 125 shot. After i run the quarters and get out of it, it starts back firing. what should my timing be? what else should i try?

 

progressively lift the throttle, that's all. many set-ups get the poping in the exhaust tract when letting off and snapping the TB closed. it's just the remaing unburned gasoline. try going down a hill in low gear, turn the ign off just for second then turn it back on, same thing happens, the unburned fuel is burning off.
Robert

 

Is the system running to rich to start with.. What does your tune consist of.
Dave