I use it as a cheap form of Lucas . . . .LOL in my peterbilt (cummins). I found that I could use only 1 quart per 140 gals of diesel. ONly problem, it doesn't have injector cleaner, so every fourth tank, I throw in dedicated injector cleaner, or ATF. It definitely smooths out the engine and improves mileage. You may also want to try Lucas fuel additive for similar results, but more expensive.