Hey Scotty! I have a 1986 Mercury Cougar 5.0 V8 with 79k miles auto transmission, runs great. I just can't figure out why it's idling a little high. I have changed the idle air control valve, cleaned the throttle body, and ran Techron injector cleaner through it. Still idles high. I was thinking maybe a MAP sensor but don't want to spend any more money on just ideas. Checked for vacuum leaks with a cigar like your video and l, didn't see any external smoke. Thanks!
If it has one, check the TPS for proper adjustment. Also, the ignition timing. If over advanced, it kicks up the idle rpm.
I will double check the timing, thank you. I don't believe it has a TPS since it's a manual adjust idle screw on the bottom of the throttle body. I have backed the idle screw all the way out and still have high idle. The timing is something I can easily check though with a timing gun. Thanks for the idea.