Classic/Antique Car Repair: 1956 Cadillac Fleetwood Sixty Special, cadillac fleetwood, wd 40

Question
Caddy seems to idle high while in Drive ... wants to take off @ stop signs I have
to hold her hard with brake. unless I shift to neutral, then she idles down.
any idea wat is causing the high in gear idle & slower neytral idle?

Answer
High C E:
Normally she should idle down when in drive. I think you may have a stuck automatic choke that's not kicking down after warm up. It may just need spraying with some WD-40 or better yet, some sillicone spray or it could be a bad air/fuel sensor that needs replacing.

Once a car warms up, the automatic choke will automatically drop down when you hit the accellerator hard and release quickly. It acts like a plunger when you do that and it releases the preset throttle that causes a high idle during warm up.