Ever since the last oil change(couple weeks ago) the truck has had very low power, horrible mileage, and surges while accelerating. Wide open or just taking it easy, you can feel it surging. It's like it tries to go but can't get out of its own way. And when I say horrible mileage, I mean 10-12 mpg. And that's empty!! Took it to the dealership, they say they fixed it, but no go. We've had trouble with the tranny before, but I believe this is all motor. BTW, mileage is 31,437.