Gas Mileage

[chetwright]

I have a 2001 2500HD ext cab 4x4 with 6.0L, auto trans. When I first bought the truck 22k miles, I got 14 mpg on the highway empty. Now at 125K, the mileage has dropped to 11mpg empty. I took it into my garage, told them to tune it up. After checking it, they said it didn't need one. I trust this garage, so I'm not sure what to think. The truck still runs great, no problems other than it pings if I don't run premium fuel. I heard it might need new O2 sensors, but not sure. With gas costing $125 a tankful, I need some help. Are there any after market things that would help?

Thanks for any help.

Chet

[slimjim2525]

When I hear of gas mileage dropping, I first think of oxygen sensors.

[omegafiler]

Pinging on regular octane indicates a problem right there. Might be time for seafoam. Then change oil, plugs, wires, and see what happens. Or just find another shop!