I have a 2002 E350 Super Duty with 50,000 miles that I bought last year with about 36,000 miles. I knew going in that it would have issues from sitting idle most of those years. New tires, brakes, front end plus a tune up when I bought it and I've replaced everything ( I think ) relating to the fuel system (sensors, injectors, filter, gas tank etc) and my mpg with just me in the van is STILL about 8.5 mpg highway. My tire pressure is correct and I don't drive aggressively at all. I'm stumped and looking for possible solutions to this.

 

OK button not clickable because engine size is not selected. Check my signature below to see why. If yours is 5.4L what's the 8th character of your VIN, M or L?
In the meantime if yours is not 7.3L you can try to run a bottle of berryman 2611, it will definitely help your gas mileage. Don't even try seafoam, only berryman 2611 will do the deep cleaning.
Additionally do you have a scanner capable to retrieve all the ford's specific DTCs (not CEL)?

 

Data stream info if available would be very helpful also.

 

Thanks for your reply.
It's 2002 E350 5.4L V8 2Wd Automatic
The 8th letter in my vin is an L
I just ordered a scanner so I hope to have some more details on that front soon. I do know that no check engine lights come on

 

They weren't known for great gas mileage, but were very dependable when properly maintained.

Most folks don't know you could carry more payload with a single wheel van than with a 14 foot dual wheel model. The addl wt of the box reduced the payload capacity.

If it never produced good gas mileage, the axle ratio of the rear end might have something to do with that.