I need Oregon fuel to break 20 mpg in our '97 Suburban 6.5T 2WD with 3.73 gears.

How does 2.7 liters move a loaded Sprinter at freeway speeds?

Here's your engine - 6.5 Diesel Engine Complete 1996

Or this - CUMMINS DIESEL ENGINE 6 CYL 190 HP READY TO GO

Or - 1989 ford/international 7.3 idi diesel engine

Sixto
87 300D