I have a VW TDI which has 176k on it. I recently had the intake manifold decarbonized and it made a huge difference not only in performance, but in mileage as well. Is this also something that should be performed on a cummins diesel as well? My cummins has over 220k on it and I feel the engine is lacking a little bit of the pop that it used to have. My mileage has also been horrible. My dodge is a 98, 24 valve.

 

hook a trailer to it and work the snot out of it. Job done. It's also very important to keep the fuel filters changed in these trucks.

 

I pull a trailer with anywhere from 2k to 8k lbs of weight depending on whether it is full or not. I change the fuel filter every other oil change. It gets a steady regimen of getting the snot worked out of it. My mileage without the trailer is about a steady 14 mpg. I would like to see it get around 19. Not sure what I have to do to get it there.