LB7 Mileage, Exhaust, Fuel

It's an '01 and generally runs great. About 4 years ago upgraded to 4" exhaust thinking mileage wud improve from 18-20. Now its about 17. No other mods except KN air filter. And, its loud in the cab now with that big muffler right underneath. Thinking about going back to stock. Wud a programmer help to mileage sitch? Also, had a limp mode last year while towing a 300lb trailer behind a load of hunt gear in the truck. Changing some older fuel lines and 1.5yr old/7000mile fuel filter solved the prob. Shud I just plan on a filter chan ge at 10k or so?

Welcome aboard!

10K-15K change intervals for fuel filters should serve you well. As for the mileage drop, my guess would be injector spray patterns/fuel atomization. Do you run fuel additives? That might be a good place to start over the next 10K filter interval...

My best LB7 mileage experience came with an ECM swap from Kennedy Diesel. He has a tow/economy tune that really wakes up and LB7, while increasing unloaded mileage. His tune is truely better than the stock OEM LB7 tune from the factory, in any measurement.

Sounds like good advice. Since I drive it so little, I'm resolved to change the filter every 10 anyway out of concern for h2o buildup. What additive might you recomend? And, where is Kennedy diesel?

I would recommend FPPF Total Power added filtration, and a lift pump setup.

I can be found at www.kennedydiesel.com