Have a friend who picked up an 02 3.9 - no o/d, 3.55 gear, 49K miles. Mileage sucks - like 9 - 13 MPG. I know of earlier similar models with o/d and probably a 2.9 gear that were getting up to 27 mpg. So I'm thinking something is seriously wrong with this thing. Outside of a normal tune up, any things to look for? Or is this typical?