Well without being able to verify any of these parts via the sensors that check to see if they are working, I would say the TFI may be bad, you can have that tested at a parts store like AutoZone or just try replacing it. The egr may be malfunctioning but I would think that would warm up faster. The O2 sensor may be faulty and causing the system to go into limp mode such would cause a check engine light and a stored code. The OD light should not be on so there is something wrong with the transmission. Perhaps a loose wire, broken solenoid or missing speed sensor. A tps may cause problems with both the fuel system and the transmission. Also the ECU may be faulty and causing all these problems. So using your doctor analogy, going by symptoms, without an X-ray, EEG, blood test or even seeing the patient, and going on the advise that the patient had some kind of procedure done by a previous doctor, perhaps a heart transplant or maybe an ingrown toenail removed, I am going to recommend brain surgery. Replace the Ecu.

 

Run a test for the possible ECU failure. The constant overdrive light being on is making me lean that direction. I remember seeing on another forum that transistors will leak and cause that part to fail.

Unplug the temperature sending unit when the truck is cold. Not sure where that is on the 5.8 maybe somebody else can help out with that. This should keep the truck in close loop.

Scan the $1200 invoice so everyone can see what parts of been replaced also. That would be a big help.

 

"Open Loop"

 

Little backwards tonight!

 

Hi, have a 92 f150 with similar prob.
Q-is it worse with A/C on?
Could be a vacuum leak.
my truck had bad EGR and O2 codes.
Replaced EGR and climate control vacuum selector valve on A/C. No Joy. This stuff is controlled by vacuum.
Taking truck in for vacuum leak troubleshooting. Will post results.

 

took truck in.
they replaced 2 vac lines and the checkvalve.
I "reset" my EEC-IV computer and so far no faults and truck runs great.