I have rebuilt motor with 9,000 miles on it and the pump and injectors have 35,000 miles smokes black used to run really good transmission has 234,000 miles on it is that the problem

how about alittle more info . temp. oil pressure. runs smooth no power, runs rough no power. idles fine. how much loss of power. does it start good all the time or hows it start when this loss of power hits. when it looses power is it a sudden thing or just slowly gets gutless .have you changed filters again since this started? how about additives to fuel. just trying to help.

It has good oil pressure and never runs a temp it slowly loses power while you drive it but has good power before this happens starts ok. I usually run dextron 3 in my fuel for an additive

Smokes black when? hot or cold? hows the MPG?

My truck recently had the same problem. Starts great, runs great until it is warmed up. Then loses power. Started thinking that the timing was in need of being done. Turned out that I burnt off a glow plug and dropped it on the piston in the #1 cylinder. Needless to say not good!!

You could have a cracked head, tore a head gasket, plugged injector from the Dextron 3, or the timing is off.

I hope it doesn't turn out to be the same as my old girl!!

My guess is his injection pump is going, mine has a mind of its own, one day its got so so power, next day it can't get out of its own way, :(

smokes black when I start it and when driving down the highway and really bad in hills I don't drive my pickup intill it warms up so i don't no if it smokes cold

I also thought it might be my pump because when it was new it made my pickup start hard when it was 32 or colder almost like it loses it prime