I finished installing a set of 305 "World" cylinder heads on my 92 TBI 5.0L camaro. For the first drive all we did was run our homade quater mile about 8 times, it drove fine. Then we looked it over and I started my drive home (which is almost 30 miles of steady cruising with 3 stops).
Half way home I noticed that the RPMs were starting to twitch a slight degree even though I wasn't moving my foot. A few miles later the RPMs would drop down to 0 then back to normal at a very fast rate. At the same time, the car would jolt forward and backward and a "Service Engine Soon" light would come on and then turn off. That lasted for a few seconds and occured 4 times.One of the times it happened at a stop sign and the car died, but started right back up. The car starts up fine and is driveable, but reliable? We advanced the timing 15 degrees and it ran good. It does not over heat, leak any fluids. has all belt accesories, stock exhaust manifolds and exhaust and removed heat shields, idles at 500-750 RPM. I obviosly missed something and am open to any suggestions.

 

It turns out that the engine code was a code "42," which was for the ESC (electronic spark control). This led us to replace the ignition moduleand tighten down the grounds and wires for the ESC. After that the problem was solved. Then we went ahead and replaced almost the entire ignition while we were working on it.
Before the heads it ran 80mph in the quarter, after just the heads installed it ran 90mph, after the Accel ignition replacement we got a comfortable 94/95mph.