Engine races

I have a 99 Windstar, has a steering problem while in park or gear. Slight turn Lt or Rt on wheel the engine power increase slightly and return to normal. I replaced the PSPS before. I notice, pulling the wire of the PSPS the problem stop, but engine dies when you turn the wheel. The motor mount are fine

Does this interfere with drivability? If not I’d leave it alone for now.

The problem might be with the Idle Air Control motor.

The Power Steering Pressure Switch sends a signal to the computer so it can bump the idle up when the power steering pump exerts a load on the engine. It appears the PSPS is functioning correctly. Because the idle changes when you turn the wheel. And the engine stalls when the PSPS is disconnected.

It sounds like the IAC motor is faulty where it’s hunting for the proper idle position when the PSPS sends it’s signal to the computer.


Only when I’m parking or backing up. If you don’t have your feet on the brake you could hit a car or back over someone.

How can I check the IAC to see if it bad, because I don’t have a code that the IAC is not working. Someone mention this to me before and told me to clean it out with cab cleaner or MAF cleaner but I still have the same problem. Do you think I need to replaced it with a new one.

Some OBDII systems don’t monitor the IAC function.

You’ve pretty much done all you can do as far as the IAC motor. And because Fords have a history of these IAC motors going bad, I wouldn’t hesitate in replacing it.