2002 Explorer, XLT, 79K miles, 4.0L V-6 (vin E), very well maintained. Spark plugs at 64000 (Autolite double platinum).
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Recently stumbles/misses/lurches under light load at ~ 1500 RPM. Very intermittent.

I just completed a 5-mile test run with OBD-II monitor hooked up, no indication of any problem. All collected data looked good. No stored or pending codes. Did it 4 times during the 5-mile run.
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Feels like you shut off ignition and right back on, but very quickly. Feels much like hitting an expansion joint in a concrete highway. Trans stays in OD with torque converter locked. All gauges read normal. The only symptom is the one quick burp. On rare occasions, will do 2 or 3 times in rapid succession, but 99% of the time only once.
Started this week, seems to be getting slightly more often. Have not yet experienced it at any RMP 2K or more (however, have not had it on the highway for cruise either). Never felt under acceleration, or moderate to heavy load.
Any suggestions?
Thanks in advance.

 

I have never had good luck with autolite anything. Pull acouple of them and check them out. I am leaning towards a fuel or spark problem. If it's not throughing a code, I'd think simple. Fuel filter, spark plugs or combo of TPS and o2 sensors. What kind of scan tool are you using and does it do dataloging?

 

You might have a coil skipping out on you.. quite common...

also possible a dirty mass air flow sensor.. try cleaning that first.

Although I believe in motorcraft plugs, I don't think they are your problems.

Try replacing once coil.. if it still does it swap with another cylinder.. and keep repeating with others until the problem goes away... of course this only applies to coil-on-plug designs... I don't recall if this is or not? (I think it is)

 

Scan tool : http://www.obd-2.com/

Yes, does data logging and I have the file. Replayed a number of times, but can see nothing that would explain the behavior.

The coil idea may be worth trying, but this has a coil pack, not a coil for each plug.

 

Changes plugs and wires today and it runs great now!!