This is discussed endlessly on the 2nd gen Dodge Ram forums with the expensive and $1,000 problem prone VP44 injection pump. I recently had to replace my VP then the new one crapped out within 100 mi. I figured that it was because of a bad rebuild then the rebuilder called & said i had gas in my returned under warranty pump. Gas (if it was actually gas) was from the diesel pump.

The above led me to pay more attention to fuel lubricity. One forum where the owner actually does some research & testing recommends 1 oz of 2-stroke oil/gal of diesel. The reseller of my VP recommends "Stanadyne Lubricity" saying that he's talked to the Stanadyne rep and looked at injectors run with & without the Lubricity. At recommended dosage & $20/ 1/2 gal, it is cheaper that 2-stroke.

FWIW, the SD runs quieter on either 2-stroke or Stanadyne Lubricity than fuel only. The Lubricity has to be bought online or from a local diesel performance vendor. The 85SD owners manual recommends some portion kerosene in the winter but that was before ULSD. I'm going to stick with Stanadyne since I need it for the VP.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.