6.0 major mpg problems!!!

[TxPSD9673]

hey guys my dad has a 06 6.0 KR and almost has 20,000 on the mileage well ever since i modded my 96 7.3 i talked him into, and he bought an afe stage 2 intake, and a turbo back magnaflow. at stock he was getting 14 mpg which is understandable for a new engine BUT after his mods he dropped down to 11! i promised him fuel economy and it just got worse im stumped any ideas on why this happened???

[Logan]

How is he checking his fuel mileage? Off the computer, or by pencil?

[TxPSD9673]

off the computer in the dash i told him they were not trust worthy but i wanted to hear someones opinion my dad drives like an old person no gunning, dragging, or anything

[Logan]

Not sure what to say. Maybe bad fuel, maybe more stop and go driving. Beats me. I would not think that letting the motor breath better would drop the mileage. Maybe he needs to beat on it a little and loosen it up

[Logan]

Oh yeah, and check it by hand and not the computer. Fill it to the very top. Not foam, just fluid. Have to do that a time or three. It takes a little longer, but that is the only true way to check mileage.

[TxPSD9673]

ya he thinks that letting it breathe better lets it burn more fuel while driving idk we will check it by hand but thanks for the opinion

[Logan]

Nah, the computer is still sending the same amount of fuel to each cylinder. So, it should not be that. Has he done the ZooDad mod. If not, truth is, he is prolly not getting that much air in there. When I had decreased fuel milage, I had an injector go down like 15%. Might want to take it and let ford check it since it will be free. Not sure. I still dont think either one of those will drop your mileage.

[TxPSD9673]

ya that makes sense no he hasnt done that mod just those 2 idk ill talk to him in the mornin

[cj41foley]

hate to hear that man, that really does suck