ok i have a 305 tbi. no cat. stock tune. tpi heads. new airtex fuel pump. new fuel filter. it starts cuttin and poppin real bad when i have the heater but it doesnt do it all the time. mainly under a load. but it can do it at even idle. really sperratic ( or however u spell that). as soon as i turn the heater off the popping quits. turn it back on and it starts up again. the backfiring is occuring out the exhaust pipe. sounds like a shotgun blast sometimes. i have the distributer advanced 4 degrees and im getting an egr code at cruise. i heard that is because with no cat it doesnt have enough backpressure to run it. but i didnt know if it would have anything to do with this. the alternator tested at between 14 and 14.5. any input is greatly appreciated.

 

Forget the backpressure comments. Backpressure is bad, although reducing backpressure can cause the stock EGR valve to not operate properly.

So, this is completely related to the setting of the heater? Then something's screwed up.

 

no it has done it before when i turned the wipers on too.