1998 k2500 6.5 Turbo Diesel

Got a slight problem. 169,000 mile 6.5 in a 3/4 ton 4x4, started acting up the other day. The girl called me and now I've got to come up with a fix. I think it got a bad tank of fuel as it was acting up last week, but then cleared up.The truck starts fine, cold or hot, but after driving for a little while (ie 5 minutes) power loss starts to occur. If you feather the pedal you can still reach cruising speeds and maintain them with no problem. If you're too hard on the pedal it'll just keep slowing down. Changed the fuel filter today, and a couple of weeks ago when I put in a lower radiator hose heater, didn't look dirty at all. Installed the new one and pumped out the reservoir, took forever to get it to restart and it never spurted fuel out of the bleed valve. I'm thinking fuel pressure is down, but could it be attributed to bad gas or is there another filter to look at. I changed the one at the rear of the intake. Thanks for reading my book and for any advice, diesels are not my specialty so I'm at your mercy.

Sounds to me like the FSD module is starting to give up the ghost.
Do a google search on the Chevy diesel Fuel Solenoid Driver on 94 and newer 6.5 diesels and see if the smyptoms match yours.

I took off the out side of the supply pump today and it barely spurted out fuel. Blew back through the tank from the in side of the pump and reinstalled the pump and it worked like new. Tomorrow I'm taking out the sending unit and cleaning the tank and replacing the sock. Pretty sure it'll fix the problem. I'll let you guys know as soon as the task is completed. Thanks for the idea Evsman. If this doesn't work I'll be checking it out.

Sock was full of hair and dirt and grease and everything but the kitchen sink. New sending unit ($110) and a couple of hours and it's like new.