Hi there, I have a 1979 Chrysler 300 with the 360 carter thermal quad 4barrell.
On the same bracket of the fast idle screw, there is a black cylinder with an electri plug on the far end, a thin wire comes out and connects to the lever the idle screw is on, any idea what that cylinder is, the wire broke and I cannot find it on any carbs I've researched.
Thanx for any help

 

Could be a fast idle solenoid

 

I'm With Lynn..... De-cell Solenoid or a A/C step up Solenoid.

I think this might be the one your looking at...
https://www.google.com/search?q=1979...21%3B500%3B297