ford explorer hesitation

Ok I Need Some Help. I Am Working On The Girlfriends 2002 Ford Expplorer 4.0l Heres Whats Wrong. Under Light Throttle There Is A Bad Hesitation. She Says It Has Been Doing This Snce She Bought It New And That When She Took It Into The Dealer They Told Her It Was Normal. Well It Is Not Normal. It Only Does It After The Explorer Has Warmed Up. When You First Start Driving It It Is Fine Then Gets Worse. It Idles Fine And Runs Great When There Is More Throttle Applied To It. I Have Changed The Plugs, Wires, Coil, Air Filter, Fuel Filter And Have Cleaned The Maf. And To No Avail It Is Still Doing It. I Have A Obdii Scanne And There Are No Codes Present. I Am About Out Of Ideas. Any Help Would Really Be Appreciated.

Welcome to this forum! Do a fuel pressure test when it starts to act up.

Ok I Need Some Help. I Am Working On The Girlfriends 2002 Ford Expplorer 4.0l Heres Whats Wrong. Under Light Throttle There Is A Bad Hesitation. She Says It Has Been Doing This Snce She Bought It New And That When She Took It Into The Dealer They Told Her It Was Normal. Well It Is Not Normal. It Only Does It After The Explorer Has Warmed Up. When You First Start Driving It It Is Fine Then Gets Worse. It Idles Fine And Runs Great When There Is More Throttle Applied To It. I Have Changed The Plugs, Wires, Coil, Air Filter, Fuel Filter And Have Cleaned The Maf. And To No Avail It Is Still Doing It. I Have A Obdii Scanner And There Are No Codes Present. I Am About Out Of Ideas. Any Help Would Really Be Appreciated.

I would try two things - first clean the throttle body, second run a can of Seafoam through the PCV valve system and another in the gas tank with a full tank of gas.
Man I hope this girl knows how lucky she is to have a boyfriend that would do all of this to her ride!!!

Also--just a hunch, check the throttle position sensor, and you might check the engine coolant temp sensor.
There are 2 coolant temp sensors, one is for the gauge, the other measures engine temp for proper fuel delivery. You might see where I made a connection to it.

I would check the fuel pressure but it only does it when it is under a very light load with minumum throttle. it never does it when it is idling or sitting still. you can run the full range of throttle when it is in ark and it is fine.

Connect the pressure gauge onto your mirror to test it while it's under a load. Check # 33 in my list of useful threads for more information.

I have mereged the 2 threads into one, and moved it to under the hood .

check the TPS with your scanner. should move smooth from closed to WOT. if you have an Advantage or similar meter you can map it and see if there is a glitch.

Heres what fixed it forme. My egr valve was fine so i traced the vacuum lines back to the egr solenoid. My solenoid had went bad. Its about $40. I replaced it but still got a little hesitation so i checked the vacuum lines and found out the the lower vacuum port on the evr is supposed to goto the egr valve. I switched them around and wahlah! No more hesitation! And my idle evened out. So i hope this helps! BTW the evr takes 5 minutes to change... so easy replacement.