Another MPG question (Sudden drop)

[nso123]

I have an 08 F250 4x4 with an SCT tuner and DPF delete. I had been getting decent mileage since installing the tuner and now the mileage has dropped significantly. (17mpg city 22-24mpg highway now dropped to 11mpg city 15 mpg hwy). The truck seems to be running fine, but I can't figure out what has caused the sudden drop. Any help would be appreciated.

[LHMissions]

Heavier right foot, winter fuel???? Just a guess or two.

[nso123]

I have watched my driving, and have been conservative driving around, with no improvement. As for winter fuel, I am not sure, I am in Tennessee, so I don't know if they are shipping winter fuel down here or not. Is it normal to see a big drop like this over the fuel? I have not heard any of my friends complain about their economy dropping this much.

[suban]

stuck caliper, lots of idle time, low tire pressure, wheel bearing, bad tc, stuck injector, etc etc

[RJD]

did you check tire pressures?

[nso123]

Just put new brakes on yesterday and all seemed fine, just needed pads. I would think that if a turbo was bad I would notice a loss of performance. I have not checked the tire pressure, but will do that. It will stink if something that simple has slipped by me.

[Barry Smith]

Sounds like it calibrated itself. Those numbers sound more like real mileages than the 17mpg city.

[dieselkane]

Originally Posted by Barry Smith

Sounds like it calibrated itself. Those numbers sound more like real mileages than the 17mpg city.

I agree. 22-24 MPG is a crazy number, and fairly unrealistic. 17-20 MPG maybe.