I just got a cai for my 87 iroc and i had to relocate the battery and some vac lines and i had to relocate my msd. When i am in first gear when the RPM is below 1500 the car seams to hesitate and miss. It also misses when rolling up to stop signs. The only thing that i did difrent was i put the msd ground wire to a frame ground but before it was to engine ground. hope you you can help.

Shane

 

Sounds like a vacuum leak. You say you re-routed some vac lines? Check them...one of them may be cracked or not on all the way.

Since you relocated that MSD ground you should check the ground strap from the engine to the chassis (I believe it's located on the back of the pass. cylinder head connecting to the firewall.) A corroded connection could cause misfires, but I'd expect it to be more of a high-rpm problem in that case.