I have a 1987 f250 4x4 with a 302efi 4spd. Motor starts and runs fine. When you start driving and accelerator peddle is pushed about a quarter of the way down motor will start to stumble and return to idle. I have replaced fuel pump in tank and fuel filters. Engine is not showing any codes. Is this a throttle position sensor problem? If it was I would think engine light would come on.

 

how are you reading the codes. how long has this been going on will it stumble when in park or neutral and did you check fuel pressure. do you have dual tanks. if you checked fuel pressure did you use a jumper and the EEC test connector

 

I am using a sunpro by actron code scanner. This started about 2 weeks ago. When it starts to stumble if you push in the clutch it runs fine. Truck does have dual tanks but I only use the front one because of a hole in the rear tank. I have not checked fuel pressure.

 

That fancy code scanner should report System Pass code 11 if there are no errors in the KOER tests and no stored codes. Anything less means your code check is invalid.

 

does your MIL work and I guess a stick don't have park sorry about that one.