[tccrab]

This has been a pet peeve of mine for a while.
I have a Haibec prom and the idle is much better than the original factory prom.
When I start the car she idles fine.
After I drive it a little while and roll up to a light sometimes the idle does not return to 600, it seems to hang at 1000-1200. Sometimes it goes down to 600 after I stop, sometimes it doesn't.
If I tap the gas slightly as I roll to a stop the idle goes down to 600.
I've always thought it was something in the throttle body, maybe gunk or something that doesn't allow the blades to close properly.
I've been afraid of messing with it for fear of f'ing up the magic black goo that seals the throttle plates to the throttle body.
In the good old days of Holly carbs you could spray cleaner down the carb with the engine running and clear gunk off of the throttle plates and stuff.

TomC