I have a 91 Z28 with a 350, SLP headers, runners, some porting, nothing crazy. The problem I'm having is when I accelerate, the knock sensor goes wild, and retards the timing about 20 deg. at times, even though there's no pinging or nothing. This causes me to lose spark advance under acceleration and the engine bogs down like crazy. When it doesnt retard timing, engine runs smooth. Just wondering if anybody else had any problems like this, maybe do to headers making pulsations? I also noticed there might be two knock sensors. I didn't look yet, but anyone know where they're at. Oh, and it seems like it does it when the engine is hot...?

 

Also where is the Electronic Spark Module on this car? I know on older ones its by the brake booster, but I looked all along the firewall and don't see it. Thanks