[JQmile]

When you drive, make sure not to be under boost at all. If the load is too high (say, accelerating up a hill) then the turbo will start to make boost, and the fueling curve will respond to the rise in boost pressure (add more fuel). This only applies on a turbodiesel of course. Oh and a timing bump will usually give a healthy increase in mpgs, 10-20% I'd say. That's why chips give you better mileage in newer computer controlled diesels, because they usually have more timing than the stockers. If you want to get nutty, you can also inject propane or cng in the intake stream.....it's a tradeoff of about 2gal of cng to 1 gal of regular fuel, but if you can get propane or cng for cheap it is well worth it.