CAR WILL START BUT ONCE PLACED IN GEAR THE CAR WILL STALL OUT AND DIE

is it backfiring? Trying to think of a condition that would result in any kinda fire at the filter... if it's backfiring, check that spark plugs are connected correctly and are firing correctly... had an issue with that with my 4 cylinder where the plug was firing too often causing a backfire and occasionally some flames coming up out of the throttle body... also check injector spray.