2004 6.0 - Poor gas mileage

[FuddleyPJones]

My 2004 F350 6.0 is losing fuel mileage. I used to average 15-18MPG and now I am at 11.5MPG.
I am wondering if a weak FICM can affect Fuel Mileage. I had it go out and I fixed it using pstrangs method but the output is still only at 40v.

I have done a few mods that while I don't see how they could affect Fuel Milage I figured I'd mention them anyway.
1) EGR Delete
2) Coolant Filter
3) Ams-oil Oil Bypass Filter
4) Crankcase Vent Re-route

The Air filter is faily new.

Could a Fuel filter do this? Wouldn't a clogging fuel filter make the truck stall or buck as an indicator?

[BeXtreme04]

40v on the ficm will definitely affect mileage as well as ruin your injectors... Might be too late to get it repaired since you tried to do it yourself but there are plenty of places that do it for a couple hundred bucks and give you a warranty on their work


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