in fifth gear there is a slight delay.. in od it is instant... it will do it in fourth at the end of the gear in a big pull/hill... I would assume they checked that out... just going by all the effort they put into it... I know they said they hooked some kind of machine on it as they were test driving it... I know these mechanics know their stuff... so im not knocking them at all... I ask them.. what is your best guess... 1 says possible weak valve spring.. other says something possibly in the motor... they are just completely stumped... both say they have never experienced this...

 

I just test drove truck.. and it was not real bad.. no shaking but not a lot of power hi end gears... next time I drive it might shake like hell... is the same pull on road... test drive conditions are the same.. I did notice.. my headlights come on when my light switch is on aux.. turned left and the inside cab light does not come on thru switch now.. but works with door open... headlights never came on when switched to the left on aux.. I noticed a 1 time clicking noise when I turned to the left... that got my attention.. maybe im trying to notice too much but this is new...

 

There are some questions of which the answers may shine some light on the problem.
1. Has the windshield ever been replaced in this truck?
2. The shaking you describe, does it feel kike it is coming from the engine or from the steering/suspension system?
3. Have you washed the engine compartment at any time?

There is a function when diagnosing called "Freeze Frame", did the people who checked out the truck mention anything about that information?

 

no windshield replacement... can feel the shaking thru stick... its the motor for sure... and no under hood washing but does not mean water has not gotten under hood... another thing both mechanics say is the problem is inter mitten ... sometimes its not there as bad... sometimes its worst

 

Has anything been done to the driveline, u-joints etc.?
Not being there to actually see/feel what you do , just trying to touch all the bases.

Hayapower offered some suggestions , were you able to try them? If so , what were the results?

Something else you might check, unplug each of the three plugs going to the PCM and see if there is any corrosion at the pins there.
Also , at the fuse panel behind the panel at the lower left of the steering column , there have been some unexplained electrical problems when moisture got into that area due to a leaking windshield (they leaked right from the factory). It is possible there is more than one problem we are dealing with.

 

u joints are solid... I ask the mechanics about fuel pressure under hi demand and they said absolutely not... its not a fuel supply problem..


the ford mechanic said he talk to other mechanics at his shop and all tend to agree that is something deeper in the motor when looking at all data and things done... (still no proof.. compression is good when in shop not driving)


I will check the electric connections tomm... thru out... I had problems with mice getting in my truck in the past... ugh.. sunflower seeds was the only damage I noticed...

 

Can you manage to get an oil pressure reading from a mechanical gauge ?
If so. allow engine to get thoroughly warmed up then get readings at idle and approx 2500 RPM. Not positive if your engine has VVT. Just another base to cover,
Another thing to try is to unplug the alt and test run it, let us know if there is any change.

Do you know if anyone has removed the valve cover on the bank with # 1 & 3 to check for any broken valve springs for those cyls?