This ones got me scratching my head and it's probably something obvious.
I can't get my idle speed below 1400! I don't mean that the car won't keep running with the idle set lower, what I mean is even with the idle speed adjustment screw backed all the way out till it's not even touching the linkage the idle doesn't go any slower. The car is running fine other than that problem. I checked to be sure the choke is fully open and made sure nothing is binding.
This is a Holley 4150 carb, 750 cfm and it's only about a year old. I didn't have this problem last year and I haven't done anything to the motor or carb over the winter other than set the idle mixture adjustment with a vacuum gauge (wound up at 1 3/4 turns out on all four), and reset the float levels, which are if anything, a hair low.
So lets hear your ideas.