Like a good Camaro, I guess, my car only wants to move. Idling is way off. After just barely warm, it idles as it should at 800 rpm (on cold days this can mean it stalls). After I drive it at highway speeds for a short distance, it will idle at about 1000 rpm. After it's good and hot, it will idle at about 1200 rpm. If I then shut off and immediately restart the engine, the idle goes back to the appropriate 800 rpm.

Background: It's a 1983 Camaro Sport 2.8L V6, with a Roch. E2SE 2bbl. carb. I rebuilt the carb, and the idle mixture screw got changed too. I've been struggling with this for a couple months, but finally have the car running great, except fot he idle problem.

Any ideas?

 

Have you checked your throttle shaft for sticking or your throttle return spring?
Tested for vacuum leaks?

 

Thanks. I just went and checked the throttle and there is no sticking and the spring is plenty strong. I've checked the vacuum lines umpteen times, and they are good. I do wonder a bit if I may have placed some vacuum lines on the wrong carb ports, but they all seemed like the logical connections, and I can't find any diagrams (not even the official shop manual has them) that show these.

 

When it is in park and idling very high (your problem), then try manually closing the throttle - grabbing the throttle lever with your hand and see if it closes any more and lowers the idle.
Also you can try capping off ALL of your vacuum lines at the intake/carb (vacuum source) side to eliminate those accessories as vacuum leaks.
Place your hand over the carb to stop all intake air at idle and if it doesn't die, then that suggests a vacuum leak.

 

The throttle seems to be set fine-I couldn't close it anymore. Great idea on checking for a vacuum leak. I've tried a lot of things, and this worked best. But still nothing; there is no vacuum leak.
I had a friend suggest it might be the coolant sensor switch. Does that make sense?
Thanks!