Rough after warming up
I have a 2002 Ford F250 7.3L that I bought new in '02. Recently the engine lost power and ran really rough. I brought it to my local mechanic who had to replace the main wiring harness and the passenger side Under Valve Cover Harness. They also replaced two injectors on the passenger side although I think they were depending on the computer too much and didn't have to replace them. They also replaced the oil pressure sensor on the driver side of the vehicle...forget the name of the sensor but it had oil in it and they recommended a replacement. I also had the coolant and thermostat replaced.
Problem: The truck runs at full power and same fuel economy as new. Once the engine reaches operating temperature the engine runs a little rough and most noticeable at idle and a little above. It seems to lag a bit when taking off from a stop. Other than the above, runs great. I have brought the truck back a couple of times and they weren't able to pull any abnormal data.
Please advise where I should start looking. It appears that once a device learns the engine is at operating temperature it malfunctions but I do not know enough about the operation of the engine to isolate.