99 Taurus 3.0 duratec rough/low idle

[mudhen33]

Have a 99 Taurus 3.0 duratec with 106 k miles on it and at a stop light, I have to rev the car up to 1000 rpm, or put in neutral and rev to get back up to 1000 rpm. It wants to idle at 400-500 and die. Just bought it a month ago, and don't know the history. It was running fine untill 2 days ago.
TIA

[mwt47]

Tuneup ?

Mike

[shorod]

If evidence shows that a tune up hasn't been performed recently, then it would be money well spent. In addition to the standard plugs, wires, air and fuel filters, check all fluids, I'd also suggest you have a bottle of fuel injector cleaner added to the fuel tank.

Pull the air intake tubes and inspect the back side of the throttle plate to make sure it's not coated in carbon. Also, make sure the air intake tubes are properly secured. You may want to consider cleaning the Mass Air Flow sensor as well.

If none of this has an effect, then consider replacing the Idle Air Control (IAC) servo. One quick test you can do for the IAC would be to turn the steering wheel all the way to one of the locks with the engine running. If the engine stalls or the engine speed drops significantly, that is a good indication the IAC is not doing its job. Don't hold the steering wheel at long for more than a few seconds though as this is hard on the power steering pump.

If it's above 39 degrees F where you live, the same test could be done using the air conditioning. If the engine speed drops when you turn on the A/C, the IAC is not doing its job.

-Rod