I posted a bulleting up earlier and got some good help so i figured I try again.

I just recently got my 91 rs back in running order. But for some reason my engine idles rough while im at a full stop. But only when its in gear. Not sure so much as how to describe it. Ill have my foot on the brake and the car will kinda jump forward real hard. Just like a sudden thrust. And its even died on my once or twice. Ive checked the timing on it with the light and its good. So i dont know if its bc of a few extra parts i put on it recently.

I put accel 8mm wires in. Bosch crossfire spark plugs. performance distributor cap. New distributor. and a new fuel filter and pump. Im thinking it may be the pump thats causing it. I think im suppose to get between 30 to 40 psi. But i got a bigger pump bc im about to drop a 327 in it to replace my old 305. Could the higher gas pressure be causing the surges to happen?

 

Get your hands on a fuel pressure gauge and hook it up to the schraeder valve on the fuel line. See if you get a pressure spike/drop when this happens (you are gonna need two people for this obviously)

Post back with your findings.

 

Does it only do it in idle? If so it MIGHT be your IAC valve. You can pull it off and clean it carefully to see if it helps. Good luck!