I just replaced the fast idle cam on my holley 4160 because it was staying at high idle and wouldn't kick back down to low idle without me manually moving the cam. Now the new cam is doing the exact same thing. I tried backing out the fast idle screw a touch and it didn't seem to help. I didn't move it that far though because I didn't want to mess it up too much. Should I just keep backing the screw out or could there be something else that is getting hung up? Could my electric choke be messing things up?

 

Sounds like a hangup. Is the choke completely opening? Something around the fast idle cam may be bent slighty and preventing it from settling like it should.

 

It won't completely open because the fast idle cam will get stuck. It will fully open once I unstick the cam manually.

 

Well, the armature the fast idle cam sits on is set by the choke, as the choke closes more the fast idle gets higher, as the choke opens the fast idle goes down until it's disabled. If the cam is preventing the choke from totally opening then the choke would prevent the cam from lowering. sounds like something might be bent, best thing is to pull the choke housing apart and look at it and play with it to find out exactly where the hangup is and fix it. I think on mine I had to do the same thing after I replaced the heating element, I stuck it back together and something sat in the wrong spot and had the same issue.