Hi guys I just picked up a 1991 F-250 Lariat with the 460 manual. The truck is clean and in very good condition. The previous owner replaced the plugs, wires, cap, rotor. He said he started one day and couldn't get it to go over 20 mph, and then it would nosedive and stall out. He thinks it's a vacuum leak. I know nothing about these. He said it will start and idle fine, but do the nosedive thing when you take off? I have not started it yet, but will likely look at it this week time permitting. Does this sound like a common problem where you guys might know where to start looking? Any help would be much appreciated!

Thanks!
Bob

 

Start here> Ford Fuel Injection » How To Run a Self-Test

And check the fuel pressure.

 

What's the mileage on that pig?

Wonder if it's not the cats that fell apart and clogging things up?

 

Thanks for the replies guys! I'll check both out. Can these run well with the cats gone if I cut them off and replace with pipe? I know the previous owner installed a new fuel pump in one of the two tanks. Mileage unknown. He was the second owner, and got it from his father-in-law. He was thinking maybe 300k but not sure. Odometer shows 67k.

 

check the bill of sale for real mileage. If you cut the cats off you may throw codes if the smog crap is still installed an working.

 

Before cutting them off, just make to sure it is that, unscrew one of the O2 sensors, the one right before the cats, and go for a drive, if it seems better, then the cats are clogged.

If you don't have emissions test where you are, cut 'em off and if that stupid engine light comes on, take the bulb out. lol

 

i removed my cat, but most of my pollution crap was gone, an once in a while my light would go on an off, i just dealt with it knowing what i had removed