My 2001 doge cummins diesel is getting real lousy fuel milage. When I bought the truck it was getting from 18 to 21 miles a gallon now I am only getting 12 to 15 miles a gallon. Any Ideas

Did you always live in canada where they use cut fuel in the winter time? It makes a difference for my mileage.

hi diesel a good place to start would be air and fuel filters, check tire press. too. hope this helps.

oh, just one more thing, keep your rpm,s below 2000 rpm, this will help for sure. good luck.

My 2001 doge cummins diesel is getting real lousy fuel milage. When I bought the truck it was getting from 18 to 21 miles a gallon now I am only getting 12 to 15 miles a gallon. Any Ideas
i am having the same problem if you find out what is wrong let me no

My fuel mileage has been quite average. I recommend the TSB that increases mileage and also recalibrates the computer. My mileage has increased a couple of mpg. Getting around 15.5-16 in town and haven't checked on the road yet.

maybe your computer has developed a glitch in its programming causing bad mileage. Maybe a re-falsh would help??.....another shot in the dark I know.

Fuels filter, air filter, or winter blend fuel would be the likely culprits.