Rough running engine

Hey all. I've got a '95 K2500 with a 6.5l in it. It started giving little signs of trouble about mid summer getting progressively worse. The symptoms started with an unusually high rev at startup, then it would run fine. It slowly got worse and really only seemed to happen when the engine was warm. Them one time I fired it up and it gave the same rev at startup, but had no power in the pedal at all, just ran really rough, but still idled ok. So I figured my injection pump was done. got out, didn't look at it for a couple of weeks. then yesterday desided to bring it in the shop and have a look, and when I did, it ran fine. So I drove it yesterday and today, and havn't has a porblem......CAN ANYONE POINT ME IN ANY DIRECTION??? A buddy thinks there is a chance that it could be the electric accelerator, but I think the trouble is too intermittent for a problem like that. Any ideas?

Any codes ?? (ses light on or coming on)

When was fuel filter last changed. Change it and make sure there is not a bunch of water/crap in the filter.

Air in the system ?? a diesel can rev up and do all sort of stuff if its getting air entrained in the fuel supply.

Place a short length of clear tubing on the fuel return from the IP and see if you are getting a lot of air.

Air will drive these electronic IP's nuts.

Check it out and let us know.

Missy