I have a 93' 12v with 5 speed getrag 4x4 with 150,000 miles and I was hauling 3-4,000 lbs. of steel to Montana last week and the truck started to feel like the tires were slipping when I was going up hills, but when I pulled into townthe truck wouldn't idle, well it will idle, but it feels like someone is shutting the key off and turning it back on real fast. You can feel the miss all through the power range, and it is very speratic, no rhyme or reason to make it miss like it does. Pump is turned up, and I replaced the shut off selenoid cuz I thought that may have something to do with it, but that changed nothing? It did get me home 500 miles and no change in fuel ecomomy??? Help....

 

have you replaced the fuel filter lately?

 

With 150K the IP may be going south if its cranked up a bunch. Swap filters and see if that helps.

 

Nope, taken it in tomorrow to get that done and the valves adjusted, could the filter be the prob?? Also the guy at the diesel repair place gave me a bottle of stuff to put in the fuel, he said I may have some water in it or something, it seems to help, but only after it warms up.

 

Do the filter first, see what it looks like, that might help to determine if you had bad fuel.
Carry a spare, too.

 

I'll tr that and let you know how it turns out. Thanks fellas...

 

Took it to the shop, they changed the fuel filter no change. They did a fuel pressure test on it and came to the conclusion that some spring in the pump has more than likely broken, he told me this was a common problem on my motor. He said truck needs a new pump! $1300-1400 installed, with adjusting the valves and doing the fuel filter and the diagnoisis fee, does that sound right.....