Hello I have a 2003 4.6 2wd f150 and the idle has seemed off for a while when the car first starts it goes to 1600-2000 rpm and hangs there for a little bit then drops fast to around 500-800 the worst part is that when I'm driving as I am coming to a stop and start hitting the brakes the eps do not drop they will hang at about 1500 until I am almost stopped and then drops down to 500 or a little lower and then it surges a bit, I have no clue what it could be it feels like I am still pushing the pedal while trying to brake anything helps
Thanks in advance for any ideas

 

Sticky idle air controller. Pull it and clean it with WD-40 or replace it. Wouldn't hurt to pull the throttle body too and clean it with throttle body cleaner, pay particular attention to the EGR ports in the elbow.

 

That's crazy cause it's brand new but I'll take care of that today thank you

 

WHAT is brand new?

 

My iac valve is brand new well at least 6 months ago I bought it from autozone

 

That doesn't mean it's any good.

Have you checked the OBD2 for codes?

 

No don't have a obd 2 reader But that gives me somewhere to start thanks for the help

 

 

Cleaned out the entire throttle body and no change i will be purchasing a obd2 reader soon so hopefully that will let me know what is wrong thanks for the help

 

Unless you are in California or Canada, you can get codes read free at most parts stores.

 

Just put the obd2 reader on and it said zero codes found I purchased the autel maxiscan ms309 and nothing came up at all any ideas

 

Also, check your EGR valve and make sure it's not sticking open causing an intake leak.

Vac Lines, something else to run down.

One trouble shooting method I've used is when the idle is dropping low, try unpluging the Idle air control valve, or the Mass Airflow sensor, or the throttle position sensor... etc...
and look for something to change.

Frosty

 

How do I go about that when I unplug and there is a change is the specific part bad or if there is no change is the specific part bad

 

So i cleaned the entire throttle body egr ports and replaced the iac valve still the same problem can't find no leaks what so ever, can it be bat tps or egr what else can it be?