98 expedition Ok i have been fighting this one for awhile. Got the code po122, which is the TPS low voltage. Replaced it, checked all the vacuum lines, checked the PCV and hoses. The IAC. I even checked the voltage to the TPS. Makes the truck do some funky shifting. But i can't get it to repeat when i run the OD5 system. Can anybody help

 

Use a digital meter and put one lead on the engine block and the second lead on the body. For both leads make sure you're contacting clean metal. If you get a volt reading of 0.5 or higher, then the problem is a bad engine to body ground connection.

Take this reading twice. Once with the engine running and once with the key on and engine off.

 

Did you mean ohm reading?

 

Did I say ohms? I meant volts, just like I said.