'94 so have the ODB-II connectors and ODB-I puter so can't pull codes... or at least have no idea what to jump on the connector to get codes to show on panel (?) just replaced plugs for Delco and wires for silicon-connects. all points on ECM show spark but at about 4K RPM while in neutral, the engine revs-drops-revs-drops. there were no problems before the spark-plug and wire replacement.

The rev limiter in Neutral or Park will limit you to 4K rpm'* because revving the motor while not in gear is extremely bad for the car. This is the PCM protecting the motor, and is normal.

That is definately the rev limiter. It is a good safety feature GM programmed, and personally I am glad they did so. You should be glad though, at least yours is at 4k, mine is at 3200, thats not much of a rev. I wish I had the extra 800rpms. Your lucky. But, yeah, definately not misfires.

Shawn

Lucky? I think it should be lower, personally. Revving a motor to that level serves no real purpose, other than long-term damage to the motor.

I don't even like revving mine to 2500 in P. They should have had a limiter on 1990 Firebirds. My brother practically was killing that engine when he had the car... 6K+ constantly.

Thanks, that'* a massive load off. Musta changed that since my old '90..

I experienced the same 35-3800 rpm bouncing on my '94 ssei and couldn't figure out why. But it was also accompanied by what I think is a misfire when I'm rolling down the road at around 1000-1500 rpm. The car just rolls along and shudders horribly. But if I accelerate it smooths out and runs better, not right, but better. Any Ideas?