I have 2 problems maybe someone could help me with. Problem # 1 is I have lousy fuel mileage (about 10Mpg) I'm running a 1994 F350 with a 7.3 turbo Deisel. Any suggestions as to how to improve this would be Helpful. Problem # 2 is I have a battery indicator light on my dash board that keeps lighting up whenever the truck is warmed up and sitting at a stop light (It go's off when I'm driving) BUT I also have a Voltmeter Gauge built into the dash Why I have both of these I DO NOT KNOW?? But the voltmeter says I am Charging Fine....The truck starts and runs fine other that these 2 small problems. Any thoughts?

Thanks,
Mike