Lots of smart folks spend a lot of time on this thread helping to diagnose issues. Thanks to all. So I just had an interesting one and thought I would have some fun with it. I'll give you all the details, take your best shot at a dianosis, and I'll let you know the outcome tomorrow. Should you guess the "next step" that reveals the problem, I'll call an end to it and let you know you figured it out.

Truck: 2001 F250 EC, 115k mi., 6637, 4" T-Back, HPX, Edge Evo II-Postion 2, WW, 203 Stat.

Situation: Truck running perfectly, fresh tank of fuel, time for a routine oil change. Changed oil with the usual Rotella (yes, filled filter first). Perfectly normal, nothing out of the ordinary. Oil change complete.

Driving down the road at oil change +5miles and I feel a slight miss. No worries, figure I'm working a little post oil change air through the system.

50 miles later, still there and maybe getting worse. Feels like a dead hole, or maybe half a dead hole. Pretty much only at idle. Presents itself as "rolling miss", i.e. comes and goes pretty regularly, every couple seconds, sometims worse than others.

Note the problem completely goes away above an EOT of 170F.

50 more miles, getting worse, can now be felt while under power at speeds up to 40 mph or so. Still goes away above 170F.

Things checked along the way:
oil level - Fine
Fule filter/flow - fine
HPOP level - Fine
Wiggle Check Harnesses - no change
IPR nut - fine
Engine codes - none

There you go. Give it you best guess (no you don't have to word your answer in the form of a question.

I'll tell you how I diagnossed and fixed it tomorrow.

 

you drained fluid out and put fluid in so.....
Did you drain your tranny fluid and add the motor oil to the tranny dip stick?

could be alot of things, I do not understand why I have to wait for an outcome.

 

Did you forget about the oil in your filter and overfill the engine?

 

That thought did cross my mind, but no. Oil qty to spec.

 

No idea, but want to hear the answer.

 

What is....You knocked a spark plug wire loose... Alex?......

What is ..you sucked a bird into your "whosyourdaddy" mod?



Really , was wondering How & or why you were reading EOT?..

Also how is it that the EOT got below 170?

Or was the problem happening on 3 separate trips?....

 

Was hoping it was something as simple as a loose spark plug wire... still can't find them though. lol

The Edge II reads out EOT as one of many selectable, displayable parameters. I just happen to have it displayed normally.

Basically the problem only ocurred as the engine heated up, every time. Once past 170 all was fine.

Note that the idiot gage shows the engine "at temp" when the engine is ~145F. No where near real normal operating temp.

 

And the next chapter?

 

Well......

 

The answer:
https://www.ford-trucks.com/forums/6...ght=diagnostic

 

It was his ICP sensor...He reported in a different post....