Pulling the Plenum for the first time...

[Schrade]

Originally Posted by Billy Mild

Now the fun starts...

Marq21 and I pulled the plenum on the ZR1 yesterday. Need to give him a shot out for helping me out on this job. Without him I would have not been able to fix the secondaries issue I was having, or get the complete job done.

First off, WOW. The car runs completely different. I don't even know what to say. If your car doesn't surprise you every time you hit the gas WOT, then you need to get some service done.

My car is having an intermittent high idle issue. It doesn't sit at the prescribed 750 RPM. It idles around 900 rpm normally, and occasionally after coming to a stop will be at 1200 RPM. With a Tech 1 hooked up the IAC shows 0. It occasionally would move, but at idle it was 0.

I have read there is IAC re-learning procedure that can be done. The battery was unhooked for a few hours. I have the FSM, but I don't know the correct search terms to find it.

-Vacuum leaks were fixed
-Plenum gaskets were in good shape so they were re-used
-Accell Injectors were installed
-Check Valve replaced for cruise
-PCV Breather hoses in the valley were replaced
-New MAP hose

The car runs great throughout the RPM's now. It drives great, except idle is a little weird. In between gears the idle will kind of hang around 1500 RPM.

Sounds like the High Idle Coast-Down issue, for which there was a GM TSB. Marc H has the chip code solution...

You might ALSO have air getting by the TB 2' butterflies, as I mentioned above.

Mouse needs butter (he's toast)