Sucky mpg

[Withers22]

I have a 2003 f350 7.3 powerstroke with 137000 miles everything is stock i am having trouble with my mpg. A couple weeks ago i was getting 16mpg i recently had my fuel bowl assembly replaced with a new filter and water seperator drain valve because it was leaking. Now ever since i had that done im averaging 11mpg its winter time but it was just as cold when i was getting 16mpg. This is hand calculated my question is why is my mpg so low right now?

[jesilvas]

Did it happen right when the fuel bowl got rebuilt?

[Withers22]

Ive filled up my tank twice since getting that replaced and got 11mpg both times

[jesilvas]

So something there changed. Might wanna check fuel pressure. The FPR might've got messed up.

[Withers22]

How could i check my fuel pressure?

[jesilvas]

There are a couple test ports on the fuel bowl on the back. You'd have to put a sensor on them.

[Withers22]

Okay thanks, if my fuel pressure is above or under what it should be what are my options on how to fix it?

[jesilvas]

Should be 65ish. But minimum 45ish. WOT it should stay above 45.
I'm not saying that's it, but because the FPR bolts on the fuel bowl, maybe it got messed up? Has the truck been running different? Any less power?

[audiocontr]

FPR rebuild kit is about $65. Its a must on any truck over 100k mi experiencing power issues.

Fuel pressure gauges can be built for less than $20. I personally went for the alternator mounted versions for $50 and couldnt be happier. I still cant believe Ford does not have a sensor for fuel pressure.

I'd bet fuel pressure is too high or you have a minor leak

[1snakedoc]

new bowl seal i would check to see if it is leaking.