I have a 89 F350 Lariat 460. The truck runs great in park, in neutral, in drive power braking it. It rev's up, no misses everything is great, until I try to drive it down the road. If I give it any more than just a touch of throttle in any gear it want to cutout and die. On a flat stretch in overdrive I can get up to about 40 mph just using a touch of throttle. I've tested the tps, the fuel pressure both are okay. It's not throwing any codes. I'd appreciate it if anyone has any info that could help. Maybe someone has experienced this same issue.


Thanks in advance.
Rick

 

If you're SURE that you have good fuel pressure measured at the fuel rail test port in this cutting-out condition...

If you have a vacuum gauge and know how to use it, you could check for restricted catalytic converters.
Need to connect to a good solid intake manifold vac source, with long enough vac hose to reach out the hood at the cowl, and in through the driver's window.

With it in Drive, and brake-torqued for a few seconds:

With a proper-running engine with no bad exhaust restriction, the vacuum reading will dip (less vacuum) momentarily as you accelerate and hold, then it will come back up (more vacuum) if you're reasonable steady on the gas pedal.

A properly-running engine with a severe exhaust restriction given the same test, will show the vacuum dip (less vacuum), and will not rise again. It will stay at a poor vacuum level, and may get increasing WORSE. If you see this, take it for a short drive. Should see vac go waaay down when you can't accelerate.
If this is what you see, try separating the exhaust system ahead of the cats, need enough of a gap to allow exhaust out. Another way is to take out the O2 sensor, even that little hole will help. Then re-run the vac test while brake-torquing it. If it is noticeably better vacuum, then you've got a restriction downstream.