i recently let my family drive my truck while i was on a business trip out of town and when i returned, low and behold, my truck was dead. it will start but only idles at or above 2000 rpm, no matter what combo of idle screw, fuel air mixture, or throttle cable tension i use it will not return to regular idle. when i press the gas it revs up to about 3.5-4k rpm and sticks there for a few seconds before returning to 2k. i have tried removing cleaning and rebuilding the carb but the problem persists. if anybody has had any experience with a carburetor demon before any help would be greatly appreciated.

To be honest, this sounds like more of a vacuum problem than a carb problem. How old and what shape are your vac lines in?