So iv gone thru the 'surging idle checklist' and it hasnt seem to help my problem. i set the base idle as instructed (unplugging IAC and checking tps voltage etc etc), i get the base idle set with the IAC unplugged (700-750 rpm) and as soon as i plug the iac back in the idle goes to about 900 rpm and stays there, surging every so often. why cant i get the idle under 900 rpm? If i turn back the idle screw any farther with the IAC unplugged itll stall. any suggestions?
idle stuck at 900 rpm? wtf?
- Thread starter Iand
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Have you tried to replace the IAC?
The IAC is a common problem with fords. Even though there might not be a code or any dirt in the IAC, many times as they get older they react slowly. Because they are working, no codes, test good, but because they are slow they cannot adjust fast enough. Idle goes high, so the IAC closes and the idle starts to drop, when desired idle is achieved, it starts to open but opens too slow so it dropps down too low, opens all the way, idle raised to desired level, startes to close, closes to slow so the idle goes way too high, and the pattern continues. I would try by replacing the IAC and seeing if this fixes your problem
High idle. These are often caused by vacuum leaks. Spray solvent around all areas of the induction system and if the idle changes, you found the area of your leak. This also could be the cause of a bad IAC.
The IAC is a common problem with fords. Even though there might not be a code or any dirt in the IAC, many times as they get older they react slowly. Because they are working, no codes, test good, but because they are slow they cannot adjust fast enough. Idle goes high, so the IAC closes and the idle starts to drop, when desired idle is achieved, it starts to open but opens too slow so it dropps down too low, opens all the way, idle raised to desired level, startes to close, closes to slow so the idle goes way too high, and the pattern continues. I would try by replacing the IAC and seeing if this fixes your problem
High idle. These are often caused by vacuum leaks. Spray solvent around all areas of the induction system and if the idle changes, you found the area of your leak. This also could be the cause of a bad IAC.
Did you reset the computer after setting base idle and before plugging the IAC back in??
If you don't, the computer adjusts idle off it's previous programming...which you changed by adjusting the idle screw
If you don't, the computer adjusts idle off it's previous programming...which you changed by adjusting the idle screw
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