1987 Grand Marquis 5.0L FAST IDLE problem

[Johnobub]

My 1987 Grand Marquis 5.0L starts up then after it warms up it will idle fast and won't stop idling fast. What can be the cause of the problem?

[miamibob]

Try looking for the "dumb" stuff first, like a linkage hanging up or a stuck gas pedal. More than likely it may be the IAC (Idle Air Control) which you should find on the Driver's side of the Throttle Body. It has two bolts and an electrical connector. I would also clean out the area of the TB it fits into while you have it off. I would also try to get a Motorcraft part as they tend to hold up better - if that doesn't matter to you STANDARD or whaqtever you can find will do!! Let us know how the repair goes!! MB

P.S. If you haven't changed the plastic grommet for the linkage I would do that also - it is right under the TB and you should be able to find a brass one as opposed to plastic that falls apart in a relatively brief period of time

[miamibob]

Sorry - make that "WHATEVER" as opposed to "WHAQTEVER"!!!! MB

[rhandwor]

I would check the TP sensor. Use an ohm meter and watch the ohms as you move the accelerator pedal.