Throttle problems with a Ford Diesel

I have a 1997 F-250 7.3 powerstroke diesel with 135,000 miles and an EO4 automatic transmission. The trucks engine light will come on and the fuel pedal will become unresponsive. Until I release the pedal then reapply pressure to it the truck will remain at an idle. Sometimes I can tell it is going to happen as the shifting of the transmission at low speed will be irratic, shifting quickly into third at very low speed and RPM. I also have noticed that the light for the OD on the shift handle will light up at the same time the failure happens. I have a local mechanic that is familiar with the 7.3 engine and he cannot diagnose it unless it is failing in the shop. It only does it while driving, and the failure goes away as soon as I release the pedal. Any ideas?

It must have been hooked up for a read of the error codes. Report the specific codes that have been read from the computer.

The mechanic says he cannot read it unless it is failing when I bring it in.

The problem might be with the Throttle Pedal Position Sensor.

The computer takes the information from this sensor to determine how much fuel should be injected into the engine, and the shift points of the transmission.


I just fixed my son’s GM diesel pickup a couple of weeks ago. A failing TPS can cause all kinds of headaches. His truck is running like new again even though it’s a 98 model after a new TPS was installed. @Tester is right on the money I think.