Not all the time but sometimes when i stop or slowdown almost to a stop it will idle down to about 200-400rpms. So far ive cleaned the MAF, IAC, and throttle body. i bought a new IAC to see if it was bad but no change still does it. Also sometimes when im stopped at a redlight it feels like it bucks a little. and if i pull off the pcv how would i diagnose if its good or bad? what else should be checked for this idle problem? thanks for all help in advance

 

wondering as well, have this happen 1 out of 200 slows/stops

 

Yeah mine happens more often then that! But it runs fine other than that

 

Did you ever figure out the issue? Struggling with the same

 

You jumped on a 13 year old thread.
The original participants are likely not involved with the problem anymore and have forgotten about this thread.

Go to the thread below for a more current conversation:
https://www.ranger-forums.com/4-0l-o...g-stop-177306/

Also, provide details of your vehicle, such as, Year, mileage (odometer) and overall condition and state of maintenance. It helps describe your problem

 

This problem only seems to happen when its cold out side. When I start my 04 ranger 4.0 v6 up it idles at 1500rpm before climbing up to 2200rpm and idling there for about 60 seconds then it will drop to 1500 rpm for a few minutes before dropping down to 1000rpm.
I have no check engine lights on after driving for a little than stopping in park it seems to idle fin and 750 rpm

 

How many miles are on your 2004?
I'd give the IAC valve a look. If it checks out bad, be sure to replace it with a Motorcraft or Hitachi only and the other brands do not work well.

 

198k miles
Truck dosnt start with IAC unplugged

 

I've read to start the engine and then unplug it. The engine should stumble and even die.

 

truck does stall when unpluging it while its running.
it did this last year where is starts up and idles at 2000-2500 rpm for 110 seconds than drops to 1500 for a few minutes before dropping to 1k. The problem just randomly started and ended last year around this time. And it just randomly started doing it again this year