M1009 Slight hesitation then surging at highway speed.

[2INSANE]

Could be air getting in the fuel lines. Could try replacing the fuel tank rubber hoses. Also check the knob on top of your fuel filter mount. Make sure it's tight. You can test it by putting a rubber hose on that nipple of the fuel filter mount and try and suck. If air, then there's your problem.

 

[Asmoday]

As far as adding 2 stroke marine oil...I have been adding 4oz. to every 5 gallons of Jet A and the truck runs great and I have been running solely Jet A since I bought the truck. I've run probably 100 plus gallons so far. I have a little mystery brew that I run now since I have been doing research on using low lubricity fuels. It 's a secret formula.... A little 2 stroke marine oil...a little Cetane booster...a little lubricity formula, some herbs and seasoning... all mixed in a very specific ratio. Chemical Jane LOVES it...LOL.

As far as your problem... I had the exact same problem as you describe years ago and it turned out to be a clogged pick-up in the fuel tank as well as a dirty inline fuel filter someone had put in near the fuel tank on the frame rails...Glad you fixed it...!