Ford Repair: ford explorer xlt, v8, 4.6 l, year 2006 engine hesitation..., ford explorer xlt, vacuum leaks

Question
Hello Brian,

I am the owner of a mint ford explorer xlt, a/t, 4x2, year 2006, v8 4.6 l. engine.

My explorer idles very smooth @ 650 rpm even with "D" gear applied, it runs very powerful and the mileage is the expected.

With no load and in parking or neutral, it hesitates a little when rpm is from 1,200 to 1,600 readings, passing the 1,600 rpm it is very smooth again, It behaves like if timing were too advanced.

The hesitation is noticeable in the muffler, it is misfiring but I no not know if is an ignition or fuel supply problem.

I suspect an EGR defective valve but it seems that it not used in my vehicle.

Could you please help me diagnose?

Everything is in very mint condition under the hood, no vacuum leaks or any hose overheated, mileage is very low 33,561 only

Answer
you are correct to assume the egr concern. I don't know the service bulletin off the top of my head but, The egr is opening at this time causing this concern and a faulty d.p.f.e. sensor is to blame or. you have a harmonic balncer starting to seperate. the harmonic balancer's in this truck we're made and composed of a weak rubber compound. it is very visual if a person were to look at it