Hmm... idle screw isn't lowering the idle?? strange. These cars as you know have lots of little gremlins. Holy crap is an understatement . My Idle is a bit high in my opinion but the mechanic turned it up because when i would drive at speed, say on the highway, then get off the exit and then lets say I arrived at a stop light, the **** thing would stall out, I didn't think turning up the idle was the solution but I guess its a lot cheaper than some other crazy solution. I digress. If you pull off a vac line does it stall?