Mileage and truck computer not overhead

[Trophy1]

Took my 03 HO to the dealers as the mileage went from 19mpg to 13. 3 running the same trip 5 months apart under the same conditions. Dealer said it was because of winter mixed fuel up north when I filled up. He also said that the computer in the truck told him how long the truck idled since new as well how many gallons of fuel burned and a bunch of qther stuff like how much the engine was under a tow load. My question what and where is this record kept. Will this also show a box? Truck showed no codes when I got this info.

Can the flash be corrupt to cause such a drop in mileage from 19 to 13. 3 on a 5 and half hour trip at 68 mph, 1850 RPM. Any help with this would be appreciated

 

[sangell]

I don't have any answers for you but my milage has gone to crap over the last seven tanks. Empty on the interstate I cannot get better than 16. 5. I used to get 19. This is at 67 mph (1950 rpms).



Scott