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Green96
10-02-2017, 06:10 PM
Several weeks ago I replaced my IAC valve with a new one from Motorcraft, no issues. Two days ago I cleaned the throttle body due to a sticking accelerator (sticking at closed). After cleaning the throttle body the sticking is gone, but the idle was high, around 1200. I pulled the battery to force a relearn of the throttle. It helped some, but the idle is still a little high (900-ish) and does not change when I disconnect the IAC valve.

I also noticed that when I rev the car it settles to a high idle (1200 or a little more) for a few seconds before dropping back down to 900-ish again.

I was always told that if the IAC valve was disconnected that the car should idle, but just barely. I am concerned that the original owner adjusted the closed position of the throttle body. I go the car in 2007 with 32000 miles. Within the first year or two I had some problems with the IAC valve. I replaced it with an aftermarket and had high idle problems. I assumed it was the off brand IAC valve. I cleaned the original and re-installed it. I am thinking the original owner had idle problems and adjusted the stop because here I am at 82,000 miles with a clean throttle body and high idle with a Motorcraft IAC valve.

Does anyone know the correct factory gap between the butterfly and the bore? I am assuming it is a few thousandths of an inch. My other option is to adjust it until the TPS sensor reads the correct voltage for 0 throttle, or disconnect the IAC and dial it down until it almost dies. I have not checked the TPS at all yet.

Green96
10-02-2017, 07:26 PM
Several weeks ago I replaced my IAC valve with a new one from Motorcraft, no issues. Two days ago I cleaned the throttle body due to a sticking accelerator (sticking at closed). After cleaning the throttle body the sticking is gone, but the idle was high, around 1200. I pulled the battery to force a relearn of the throttle. It helped some, but the idle is still a little high (900-ish) and does not change when I disconnect the IAC valve.

I also noticed that when I rev the car it settles to a high idle (1200 or a little more) for a few seconds before dropping back down to 900-ish again.

I was always told that if the IAC valve was disconnected that the car should idle, but just barely. I am concerned that the original owner adjusted the closed position of the throttle body. I go the car in 2007 with 32000 miles. Within the first year or two I had some problems with the IAC valve. I replaced it with an aftermarket and had high idle problems. I assumed it was the off brand IAC valve. I cleaned the original and re-installed it. I am thinking the original owner had idle problems and adjusted the stop because here I am at 82,000 miles with a clean throttle body and high idle with a Motorcraft IAC valve.

Does anyone know the correct factory gap between the butterfly and the bore? I am assuming it is a few thousandths of an inch. My other option is to adjust it until the TPS sensor reads the correct voltage for 0 throttle, or disconnect the IAC and dial it down until it almost dies. I have not checked the TPS at all yet.I just pulled it back apart. Tps reads 0.96v at closed throttle. I can get 0.004" feeler gage between the butterfly and the throttle body with moderate drag when I pull it out.

I have to admit that I reused the throttle body gasket. I think it might be the issue.

Green96
10-07-2017, 08:30 PM
I just pulled it back apart. Tps reads 0.96v at closed throttle. I can get 0.004" feeler gage between the butterfly and the throttle body with moderate drag when I pull it out.

I have to admit that I reused the throttle body gasket. I think it might be the issue.

Idle is back to normal after the new throttle body gasket. It still holds a slightly higher rpm for a very short period after revving, but everything appears normal. It does not die when I disconnect the IAC valve, but the idle does drop way down as it is supposed too.

I am also feeling it kick down more freely during normal driving which was the other problem I was having. Overall I am not sure it has run this well for as long as I have owned it. I think something has been off in the throttle body/idle for a long long time.