First off, this is for 8D. It's a 305 with an HSR, LT1 cam and LT headers, a t56, and that's it.

I'm sure this is talked about a lot but I seem to get this weird idle surging once I go into closed loop. I'm not really sure why. From what I can tell it goes real lean, rpms drop and the computer tries to counteract and hold idle by dumping tons of fuel in but always seems to over compensate. That seem right? It's right around 35-40kpa and the revs go from 400-1200 and anywhere in between. I've tried setting spark advance on a sort of plateau all around that area and have tried leveling the fuel out so any changes aren't too apparent but it still seems to do it. Ideas?

And my second problem the best I can describe as a sticking choke. When cruising around the car will hang rpms in the 12-1500 range unless I come to a complete stop and tap the throttle. Where would I start fiddling with this?

 

For the high idle and pedal tap, it may be that the TB is sticking ever so slightly. If the TPS% doesn't return to less then 1% then the ECM will not go into idle mode. Can crutch this by increasing the TPS% threshold for idle. Or put another throttle return spring on the linkage.

RBob.

 

Is your O2 sensor heated? Maybe it's a bit cold in the long tube headers causing it to be too slow.

 

At idle the TPS voltage is .71 and WOT is 4.XX something. This seems to happen and the tps voltage is anywhere from .71-.73. If I come to a complete stop and wait 5-10 seconds it'll fall back to a normal idle. It's bugging the crap to have this sticking.

The O2 is a heated ACDelco unit...