95 mustang 5.0, stick shift high idle problems

HI. I have a 1995 mustang 5.0, stick shift. about a year ago I started to have a problem with a high idle (1400 to 1800 rpm). It may just be a coincidence but, it started to happen one day after the car had overheated. I have replaced the TPS and the MAF sensor but, still cannot get the idle to come down. the oddest of things??? I can be doing 55 mph and push the clutch in and the idle stays the same (right around 2200). it will not come down until the car itself slows down. I have tested this numerous times hot and cold and it always happens. as of now... I'm sort of stuck on a direction. any suggestions?

I assume your throwing no codes.

This may be throttle or cruise cables sticking. You can disconnect and see if idles and rev's when cables are off,see if TB comes back to idle stop. Good luck

nope. not throwing a single code but you can tell the computer is trying to adjust for whatever is going on.