missing and back fire 87 stang
 

when i punch my car she is missing hesitation even when i floor it and she will back fire at slow down or first take off, new map throttle pos pcv new engine with maybe 5k on it i put all new vacuum lines all new electrical emission control shit it wasent this bad 7 months ago but im driven it more she is missing more. plugs are new gapped right new wires timing is set right new fuel injectors new fuel pump fuel filter im stumped plz get back with me thanks diane