1997.5 wagon 6.5 turbo diesel. 80,000 miles. dont know if all H1s are like this but, when going down the road at speed(anything above 35) the truck is either accelerating or off the gas. so i can cant sustain one speed. i am either speeding up or off the throttle. when i hold the peddle in one spot and it reaches the speed that the motor can push it at, it starts acting like i am on the gas accelerating then just letting off and the truck dives forward then i give it some gas again and it takes back off again. so it will be lurching back and forth unless im accelerating or going up a hill. i think that it might be an injector pump out of adjustment. the faster i go the worse it is. i dont ever go but a few miles of 60 at the most. most the time im at 45-55. any ideas?

 

When my injector pump went bad not only did the truck stall from time to time, but it also lurched forward at a stop light. I about ran over a honda civic when that happened. It never did it while moving thought so I dont know. Also I remember reading on flashoffroad that they way these make boost are kind of weird. They dont make it constantly and make a lot more when taking off than it goes down to 2 or 3 while driving (dont quote me) Anyway maybe it could have something to do with your turbo?