We just recently bought a 1992 F-150, about 3 weeks ago, and it has been working perfectly until last night. We bought it from a good friend who barely drove it, changed the plugs, gave it a tune up, oil change, new tires, the works. Since the beginning it took a bit longer to accelerate which we figured that it may be normal since its an older model, but last night it was having trouble getting past 35 mph. This morning my bf was driving it to work and was not able to get it over 35 mph, and after a bit he couldn't get it to go over 20, then 10, then 5 mph.

Any suggestions?

 

Check for a plugged converter and change the fuel filter.

 

Thank you for the quick response! I will definitely get that done right after work. Hopefully that is the issue.

 

Have the fuel pressure checked.

 

I'd be more inclined to think throttle position sensor. That's about how the one went out on my Bronco. Fuel pressure, I wouldn't think so as these trucks will just shut off at 35lbs fuel pressure by design. Converter is a good one to check though.