Idols high when comming to a stop wont idol down

Hi Doyle:
Have you backed the throttle stop off all the way?

Have you checked for vacuum leaks ?

Spray a small amount of starting fluid around all suspected areas and if it revs up that's where you leak is.

Possibly the idler control circuit board. I changed out my fair share back when I worked on them. Also, check your idler solenoid. I can't remember if those pulled in to idle, or pulled in for high RPM's. May be something as simple as rust on the solenoid plunger.

put 12 volts to the coil and see if it pulls in. Could be coil, idle module, ignition switch, or wiring. Get a 12v test light and trace it.

need to idle it down and adjust the carb

Hi and welcome to FixYa,

Almost always, the described idling problem would be a carb issue. The carbs set has to be pulled down, fully dis-assembled, all non-rubber parts soaked in carb cleaner and cleaning be done specially on the jets and pin holes.

In some instances high idle could be caused by a vacuum leak in any of the rubber coupling between the carbs and the intake manifolds.

Good luck and thank you for asking FixYa.

I have the same problem.... now it's getting worse and idling higher....If you find out the answer please email me at [email protected]... thanks

either the tps is out of parameters or you need to adjust the idle up a bit

Hello, here is a thread I found on this site with from what it looks like, the same problem(with an added solution) that you have. http://www.fixya.com/cars/t1576683-1999_cougar_diagnostic_code_p0430_p0420

if you can pull back on the gas foot pedal and it will idle better then it might of just started doing this. spray some throttle body cleaner inside the throtle body where the throtle opens and closes. build up should be the first cause because it wont let the throttle plate close. other wise check for a vacume leak.