On my buddies '79 we've been trying to figure out a weird little quirk.
After the car warms up and you are driving, the RPM's are slow to come down when you let off the throttle.
Checked the linakge to see if it was binding or hanging up... no
Lubricated the linkage to be sure, pulling up on pedal when the RPM's "Stick" doesn't help (Had a similar problem on mine and that was how I figured out it was the linkage).

Otherwise the car is running great right now.

I'm thinking maybe vacuum advance on dizzy, but it's a new dizzy and the problem was there before the dizzy was swapped.

Any ideas anyone?

Rod.

 

Sounds like a vacuum leak somewhere anyway... start w/ the dizzy first tho... good hunch.

 

If it's not a vaccum leak, and you're sure the linkage is not bent anywhere, just add another, or stronger, return spring. btw: Are you sure the return spring isn't missing or broken?

 

Yeah, the linkage is clean and clear and it is not binding up. It returns all the way back on it's own cleanly.

It only has the sypmtom after it warms up, and it only does it when you're driving... if you have the car sitting there with the hood up and running, it won't do it... weird.

Rod.

 

It could be that you have the vacuum lines hooked up improperly. I seem to remember my car having similar symptoms after I rebuilt the engine. It was because my vacuum line were all mixed up.

 

Do these cars have the old style vaccum diaphragm that holds the throttle open for a bit when your driving down the road? iirc they didn't do it while sitting still. If so, maybe the rubber part is torn and hanging up inside, holding the throttle open.