- Moderator
- #1
I was tied up on an 08 SD with a 6.4 last week, replacing a high pressure pump and gasket. When I started it up, it had a check engine light. The customer had to have it for a trip to PA. He brought it back today. Handing me the keys, "Dont screw it up. I dont know what you did, but I got 26.8 mpg, with ungodly horsepower." The pipes are clean, with no soot. He figured the mileage with both, hand calculations, and lie o meter.