I have a 2000 Z24. Recently installed new motor and venom intake manifold as well as pacesetter exhaust header. Cannot get the car to run right. It's actually slower than it was when it was new. When car is initially started up when very cold, sputters and revs up and down. I've had it checked for vacuum leaks, replaced the 02 sensors, coils, coil caps, plugs. Wondering if anybody has any advice on why it's running wrong. Do I need to have the computer reflashed?

maybe its a A/F problem



Im a Xbox 360 fanboy...and damn proud of it!!

does it idle ok for a minute or so, and then go up and down every second?

I had that happen to me once, it was a vacumme leak. Maybe the seal between the intake manifold and engine is not a good seal.

Or maybe, the throttle plate (butterfly valve) needs to be adjusted to be closed more. It may be letting too much air in. Look for a screw to adjust a stoping item to keep the plate from closing all the way.