Originally Posted by beenthere
here is a post in the Cummings forum
Okay... just returned from a 3,000+ mile winter trip and have a lot of questions and issues. This one is; who of you have added performance chips to your ISB 275 HP Cummins, and do you see a significant improvement in power and/or mileage? Mine does fine on flat or gently rolling ground but suffers badly on long and/or steep grades. I can live with it, but 35 mph on Interstate grades is not fun!
'99 Diplomat 38A- "High Plains Drifter"
'02 Wrangler Tender
Chip will get you more power but forget about fuel mileage. With more power comes higher speeds thus less fuel mileage.