Isn't it supposed to shut off? If i can close the screw completely does it mean that it's bad??? when i open it up alot it just changes the idle SLIGHTLY. It was changed 2 years ago with a Ford part and cleaned last year
How are you closing the IAC switch? It uses PWM, not an on/off switch.
As for the bleed screw (the allen head adjuster underneat a plastic plug), it is just a controlled air leak. The idle never changed a whole lot when I played with it but it would create a hanging idle when the engine was revved and allowed to fall back to idle. If you run it all the way in, the car should NOT stall. And you can generally run them out safely about 1.5 turns before a hanging idle crops up.
I prefer to adjust the idle with the stop screw, though some folks do not like to do it this way. It works well IMHO as long as you don't go way over the commanded idle.
Sorry about calling it a switch, i ment the iac valve and the bleed screw on the throttle body, so my iac should be ok then, i turned it open like 2 turns and now i have a slight hanging idle while shifting which i think makes my car feel like it accelerates smoother.
I might be missing the boat, but your adjustment and characteristics sound about right to me. The extra air you're bypassing will make the engine not return to idle as quickly after you let off the gas, as you've seen.
If I didnt add it before, the throttle stop adjustment kinda dictates what happens if the IAC bleed screw is adjusted or if the IAC is actually disconnected (electrically). I keep my idle adjusted where I don't need an IAC at hot idle, for example.