double check the tension on your throttle cable then. Not sure if you have one of them old style 10 lever throttle linkages or the good kind thats just a wheel on the butterfly shaft, but either way, make sure there is sufficient slack in the cable so that it can return the butterfly to IDL location. Another thing, lube the throttle cables casing.

Just to make sure Im understanding this all correctly, with new throttle body installed the engine behaves perfectly normal and fine, until after driving and coming to your first stoplight, then it goes into a high idle?

Make sure your cooling system is fully purged of all air, that all hoses and vents to the plenum are sealing tightly and arent cracked. Next- make sure your idle is to spec and not set to high. The fact it runs normal until coming to a stop after driving it, makes me think the problem is really simple and just being overlooked. Hows the condition of that return spring? Next time it does this, pull over soon as you can, get out and manually work the throttle shut...if it shuts to the IDL location with your hand, the problem can be easily solved.

~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />