Hi List , A friend of mine has an '83 Imperial onto which he has grafted the throttle body injection system (in toto) from a 1989 Ram Charger this has worked well for a number of years however, he is now getting a backfire thru the TBI up and out of the intake. This happens most frequently when the car has warmed up and is shifting from low to second or when an acceleration load is on the engine - not when he is simply cruising. Anybody have an idea what is causing this to happen? All help greatly appreciated. Marc 67 Coupe (now with fully functioning T&C AM/FM Radio & Brake LIghts)