i put my remanned 350 in, recently and was taking the (1982) k5 for a spin, wednesday night. ran fine except for an off-idle stumble, probably from being rich. but, when i started it up the next day, the idle was insanely high and wouldn't come down. i couldn't even change the idle by putting my hand over the primaries. replaced one vac line and now the hand on the carb slows it, but it will not slow down on its own. i tried carb cleaner and propane around the carb and manifold but can't find a leak. i do not know why this would happen overnight without me toching anything. should i be looking for a broken part on my q-jet? my only long-term experience with carbs is my old honda 2barrel, so i'm feeling in the dark on this one. i appreciate any advice. thanks.