Hello to all other Ford truck friends! I have a 1991 Ford F-series 460 V8 on a 2 ton chassie motorhome. The problem is that with run and drive fine then all of a sudden it coughs and pops thu the muffler, bucks like a pony, misses and loses power. Pull over and it gathers itself and will run again. Runs fine at idle. Take off and it OK for a few yards than feels like it flaten out no power. with pick itself up again. It also has simaler problems with hot weather. I have been told several things like a fuel pump problem or themostant, etc. What do you think? I sure will appreciate all answers as I will not drive it anymore untill Im sure I've corrected the problem.
1999 Ford F-250 Lariet 7.3
1991 Ford 460 motorhome
This would be a lot easier to answer if it was a 1981 instead of a 1991 as they were famous for these symptoms.
Well it sounds like lean fuel symptoms. Some have added a inline boost pump along the frame and wired it in parallel with the pump in the tank and it has seemed to have worked out well for them. To check if this is the problem you would need to put a fuel pressure gauge on the engine and when it does it check the pressure. You would most likly be at WOT when this happens so the fuel pressure should say at about 40 PSI during the WOT. If it drops down to the low 30's or below then you would have to either put the inline frame pump on or put one of the new stile turbine pump in the tank.
Ford has a TSB out about the problem and the new stile pump to fix it.
If you want to see the TSB just email me and I will send it to you as I can not no long post PDF's on this site.
My email address is below in this post.
Also if you want to do me a favor could you send me a photo or information off the PCM Computer. I would like to know the Program Code and the part number off a 1991 F53 for program modifications.