1985 cutlass supreme v6 3.8 My car has been idling high in 20,000 rpm range and I saw that after the car is fully warmed up the carburetor flap is almost closed and if I push down the a little metal tab by the passenger side towards radiator primary choke the idle goes down and the flap opens and idle drop down to around 800 and in drive it lowers more, but if I rev the engine the flap closes again and and rpm go up again, what could be causing this? thanks. 
