I have a Holley Street Advenger on a new motor. When I fire it up I will warm it up until the fast idle/electric choke goes off. On the way out of the driveway the car idles very smooth and nice. After I get the car to cruising speed and come to the first light or stop sign, the motor returns to the fast idle. This really puzzles me since I'm a novice at carbs. I can get the car to smooth idle again by mashing the clutch in and revving the motor. Any help in figuring this out will be appreciated.

Hey Aaron,

You might want to check your springs in the distributor. Your problem reminds me of one I had once. One of the springs were broken in on my distributor causing the motor to idle high at stop lights. It we be fine for a little while, then it would ldle high again.

Also make sure the blades are closing all the way. Make sure the return springs are good.

Aaron

Is the choke trying to close? maybe check the choke adjustment.

Also check that your throttle cable or rod is providing enough forward motion to allow the throttle blades to easily close. Most likely just a return spring problem, or binding linkage though. Does it do it only while driving when the engine is under load or will it do it in a parked position as well?

Thanks guys. It only does this when the car is under load.