Topic: engine revs up and down on it's own.

[kansascdr]

I just had the carborator rebuilt and it was set to factory specs. The problem is that after the car warms up it almost always dies when I come to a stop sign. In idle it revs up and down on it's own. This is a 68 with a 302 and 4 barrel carborator.

Anyone have any ideas

[66GTKFB]

You may have a vacuum leak. Check the distributor vacuum diaphram, especially if you have one of the advance-retard features on it.  Use a piece of rubber hose on the ports and with the distributor cap off, see if you get movement some "mouth" vacuum. You may also have overcompensated for your problem by increasing the idle.
Jim

[carlforman]

Air leak, could be as simple as the carb to intake  gasket.  My car did that after I put a new carb on, no amount of adjusments fixed, I took the carb off, and put a new gasket on, bolted it up, tuned it, now it runs good, idles right.