Hi, I am a proud new owner of a 94 diesel f250 xl. Although, the overdrive light is flashing and shifts really hard sometimes.... my mechanic replaced the throttle sensor, and doesnt seem to do it as often. it will go days running perfect with no light. but randomly malfunctions. is this a common problem??? his transmission diagnostic tool has problems talking to the truck. i need help!!

 

Nope, there's something wrong with the transmission, that's why the OD light blinks. The hard shifting is because it's running in limp mode. Might wanna get those codes pulled before something happens. Might just be some wiring/plug issues, a lot of times they get corroded or loose at the connectors on the transmisssion.

 

Ford Fuel Injection » How To Run a Self-Test Here is a link on how to check for trouble codes without a code reader. You would probably have to wire in a small test light or meter as shown. You would also have to keep the gas pedal to the floor during the test (engine off) to avoid a false TPS code.
You could also buy a OBD1 code reader such as Equus 3145 for around $30.00 to make life easier.
Getting the trouble codes can be a big help in finding out what the problem is.