endrnet

I'm working on a swap project. Engine is an L33, with corvette intake and f-body accy drive.

Exhaust is finally complete.

PCM was shipped to me with vats disabled, rear O2 sensor delete, and tuned for the 26# injectors from the intake.

Starts RIGHT up, loud, but no hesitation at all to starting.

A quick rev will send the motor up a few k rpm and it comes back to idle very slowly. VERY slowly, and I'm not sure it actually ever returns all the way.

Now, the PCM hasn't had much time to learn the motor, and I have never let it fully reach operating temperature since I still have to setup the fan relay, but everything else is hooked up.

I had a C5 before, and even COLD, it wouldn't react this way.

Any ideas? IAC is brand new, but I'm wondering if that's not the culprit...

71novaguy

iTrader: (2)

I'd like to see the answer to this too. My T/A is stock and does this occasionally. It also does this on occasion when shifting. It will hold some rpm when I'm shifting. It actually works out nice when it does it cause its almost like rev matching..

99bluehawk

iTrader: (11)

My car use to do it when I had the air pump or what ever its called. I have a 99 Pontiac Trans Am Firehawk and I only had lid and full exhaust. I eliminated EGR and replaced LS1 with LS6 intake. Now it revs pretty nice and the idle is consistent. Fast return to regular idle also.

-Bert

lt1pwr1

iTrader: (1)

Have you done a crankshaft variation relearn with a Tech 2? I would try that and see if it helps.

Sales2@Texas-speed

iTrader: (5)

It could be a small vacuum leak or something bunk in the tune.