88 GTA 350 sometimes my car doesnt like to idle right at stop lights, runs great on the highway, just in traffic it sucks, i have to put it in neutral to keep it from jumping.

But i noticed that when my check engine light comes on, it runs great like a brand new car. Its like a sensor or something trips.

i did all new tune up, but i also put in a k@n cold air intake, also new headers

My question is i was at a car show tonight with my car, and was talking with this guy, who said that since i put that stuff on headers and filter that i need to reprogram the computer to adjust for the headers / or get a new mass air flow sensor

anyone know about this Thanks