2002 Explorer idles high when slowing down

[MrLucas33]

Hey, I have a 2002 Explorer 4.6L and I recently changed the IAC valve because when the car was cold it would not stay on. Changing the IAC did fix the issue of it not staying on when it was cold but now I find it pulls hard as I slow down to stop and once I am about to stop the rpm's drop and it does not pull. If I am coming to a stop and feel it pulling hard then I sometimes click it into neutral and the rpm's jump to around 1800-2200 but once I stop then they go back to 600-700. It does not do this all the time but most of the times it does. I was not sure if it could be a TPS issue or something else? It never was an issue when I had the bad IAC valve installed. If someone knows something I can check then please let me know.
Thanks

 

[Mustang Guy]

Have you cleaned the throttle body and plate? If not, do so, a carbon buildup there could cause your problems. Only use "Throttle Body Cleaner" and definetely not "Carb Cleaner".

 

[MrLucas33]

Ok, ill try that and see what happens but just a quick question, would the temperature affect that? I fine that on warmer days it does not have that issue but on colder days it does? Would you still say it is a carbon build us issue?

 

[Mustang Guy]

Temp could affect it. I still would clean the throttle body because the carbon would cause the throttle plate to stick. If you have more than 75k on the odometer it needs cleaned no matter what.

 

[lincolnshibuya]

what brand of IAC did you use? aftermarket IAC are a hit and miss thing.

 

[MrLucas33]

sorry for the long wait to reply. not sure of the brand of the iac valve. also I did end up cleaning the throttle body and it still made no difference. I also ran some seafoam into the air intake to see if that would help but nothing.

 

[1996EB]

My 03 4.6L will sometimes exhibit similar symptoms, but not as severe as yours. I find that if the motor is cold and I start the vehicle and drive off quickly, it will have a slight rev issue when coming to a stop. The best way for me to avoid this is to let the engine "warm-up" for about a minute or two on a cold start. I wait until the RPMs drop to about 800 before putting it in gear. If I don't wait and drive off while the car was idling at anything over 1000 the rev issue will happen when coming to a stop early in the drive. This procedure works for me every time- just wait until your idle drops down to about 800 before driving. I hope this helps.

 

[MrLucas33]

Even with the engine warmed up it still causes the same issue.

 

[MrLucas33]

what brand of IAC did you use? aftermarket IAC are a hit and miss thing.

It was a BWD iac valve. I found that when I drove with it with the iac disconnected it ran much better. I replaced it again just now and it still has the same issue.

 

[Dr_Z]

Bumping to top.
I have the EXACT SAME problem with my '02 Exp. And I do the same shifting to neutral... Don't want to wear out the brakes so fast...
Any resolution?

 

[Dr_Z]

I fixed the problem and posted here:
http://www.explorerforum.com/forums/index.php?threads/high-idle-surge-when-stopping-fixed.453515/

Turned out to be the IAC.