Have you adjusted the screw under the throttle body? I think that's in the FAQ.

Also is your dashpot in good shape?

Dale

 

Is your PFC returned to stock settings? Is O2 feedback on or off? Has it been reset and allowed to do the idle learn procedure?

In my experience it's really best to stay away from throttle body adjustments on these cars and FC's. You can really back yourself into a corner because there are so many opportunities to screw up. There is a great guide on TB setup floating around and if you join the PFC yahoo group you can download it there.

 

I did adjust the screw under the intake elbow to be turned 1/2 turn from fully closed, like the instructions said. My coarse idle adjust screw may or may not be back in the original position, it's hard to say at this point. I'll need to learn how to (re)set that.

I reset the powerfc before I started the car with it for the first time. The only settings I've changed so far are the idle speeds, so I assume O2 feedback is on. I'll check the dashpot too. I haven't touched it yet.

 

It took a week of tinkering, but I got my idle set almost perfectly now.

I basically tweaked my TB screws until I got them to work, since there isn't any procedure to set these in the service manual. What worked for me was backing the coarse adjust screw all the way off to where it wasn't really doing anything, and then I played with the air adjust screw under the intake elbow. Initially I had it 1/2 turn out and I tried more and less air, but in the end it idled best and had no surging when the screw is all the way in. I did have to reset the powerFC after each adjustment, so it could relearn the idle. I'm now on the default settings, 720/800rpm idle.

Sometimes, the idle seems to get hung around 1k, without surging, and blipping the throttle seems to make it drop. That's the only issue but it's minor. My dashpot works, throttle cable is in spec, TPS voltages are good, sensors working, etc.

For anyone who finds this thread in the future, the coarse idle screw (pointing straight up w/ 8mm lock nut near dashpot) had EVERYTHING to do with my surging idle. I wish I'd never changed it in the first place. I'll just wedge something under it if I need a brand new engine to idle higher for a minute.

 

This X 1000. Been there.

If it keeps giving you trouble I would join the yahoo tuning group (contact Arghx or cewrx7). The tuning notes section of the group has an excellent guide to setting up the throttle body, which I have used succesfully. In addition, if you plan to mess with PFC settings the PFC tuning notes are a must-have.