So back to got2befast's original questions...

I think there are numerous posts in this forum on where the codes reside for the keyless entry system. I was fortunate that the PO left the card in the console...

Gas mileage - I get around 15-16 in town and 18-19 on the road (65-70 not towing) in 2WD. Mileage is worse during winter months due to the fuel they sell. I've also found that name brand fuels give me around .4-.5 MPG better mileage. Also the fuels with 10% ethanol are good for about a 1-3 MPG drop.

All in all not bad for a 6500+ lb. vehicle w/4WD. You don't say if yours is 2WD or 4WD...

Improving the MPG? Not much you can do. Drive gently. All kinds of gimmicks out there but if you read all of these forums there's no magic elixr that's going to do much for you.

B/R,
Randy