I have a 1974 xke, just out of the restoration shop and the throttle doesn’t return to idle. When you take your foot off the gas it stays at that rpm until you quickly tap the gas and then it goes back to idle. Any ideas?

 

Pretty common this. Linkages a bit gummed up. Clean everything with gunk or similar and see what it's like then.

 

If you have twin ZS carbs, with Auto transmission, then this is linkage that needs to be Isolated to find where the "stickiness" is.

Disconnect (item 12) at top to isolate FWD shaft from Firewall. if FWD then it could be (1) throttle plates in carbs or throttle plates in manifold.
(2) throttle cable (item 18)...disconnect the short link (no item number) at FWD location of Auto kickdown assembly. Cables do fail internally after many years.
(3) Loosen a clamp on throttle shaft between carbs, to see if either one is sticking. Each carb should return to idle with shaft clamp loose.

Lets us know if you need more specifics.
Rgds
David

 

Thanks for your help but it is a 4 speed manual transmission. Thanks

 

The throttle is fine when the engine is cold, but when the engine warms up the throttle sticks and you have to tap the gas for the idle to come back down. Thanks