Monaco fuel mileage

[mizoola]

We just bought a 2006 40 foot Monaco Knight with 2 slides, full wall with bath and a half. The fuel mileage isn't good. We're lucky to get 7+ MPG with a 330 hp Cummings diesel. It also has no power. Takes forever to get up to speed and need LOTS of room to pass anyone. Our previous motorhome was a Newmar Dutch Star, 38 feet with one slide, had a 275 hp Cummings, had lots of power and got 10+ mpg. Any suggestions on how to improve this? You wouldn't think both power and mileage would be bad. You usually give one up for the other. Better mileage, less power. More power, less mileage.

[pplummer]

Being low on power could be a bunch of things. Anything from a plugged fuel filter to a turbo connection loose, but it should have plenty of power. I'd start with a reputable shop unless you know you've changed the fuel filter recently.

I have the Baby Cummins also (275version) and I consistently get 12 not towing keeping it under 65MPH. My worse tank was 9MPG through the mountains. I'd wait for a response from somebody with a similar weight / length unit.

[Meandering Retiree]

Check your filters, air & fuel. I have a Monaco 370 hp and I have an average of 8.54 for the life of the coach according to the computer. 9.5 on this trip from IL to TN.

[saduncan1]

I would get it down to your local Cummings dealer and have them plug their Laptop in to it. Should you have a plugged exhaust, air filter or fuel filter this should show up with a low Turbo boost pressure, low power, poor fuel mileage, the Cummings dealer should be able to fix you up!!