I dont really keep track but I know I average around 19mpg highway when I go on trips(and thats usually some kinda of pass or mountain climbing every time) I've seen over 20 on flat highway!
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2002 7.3 F250 Supercab Shortbox
DIY intake
CCV dumped
Autometer gauges
WW/ATS 1.0 exhaust housing
Hutch/Harpoon in tank mods/hpX line
AIH delete/ebpv delete
TruCool trans cooler
Straight piped
PHP FU