2000 F250 V10. 149.5k miles. Fresh plugs at about 110k. I used Motorcraft plugs.
So my fuel economy has dropped to under 9 mpg from about 12.5 combined and 9 towing. I have seen this gradually with a dramatic drop in the last year. I used a scan tool and no codes came up. It starts and runs fine. I towed with it last week and it worked out fine. I run a K&N intake kit with Gibson cat back system and have since it was pretty new.
I am leaving on a short trip next week and want to try to avoid 6.2 MPG I got on my last towing trip, about 240 mi.
Without any obvious signs or symptoms showing, what would you guys here recommend looking at to try and get some of my mpg back?
Thanks,
Steve

 

Does the bad fuel economy come and go with summer vs winter fuel blends maybe?

 

It doesn't seem too. We should be switching to the winter blend here in California shortly.

 

I would be sure you don't have a stuck brake caliper. My front pass side was hung up and my MPG went from under 9 to 11.5.

Do any of your wheels have excessive brake dust?

 

Like Boss mentioned check the calipers, its a common problem with these trucks.


Next I would clean the MAF and run some fuel treatment like chevron with techron or some seafoam. How is your fuel filter? Been changed recently? PCV Valve and hoses connecting?

 

I agree, those K&N filters pass as much dirt as they do air (combined with the oil you spray on them), partly fouling the MAF sensor. I'd check for vacuum leaks, PCV valve and clean the MAF sensor with some of the CRC spray specially designed for MAP and MAF sensors, before you throw parts at this issue. K&N air filters cause more problems than they ever solve.

 

Well, I haven't had any problems with my truck. $300 in shop fees, the rest I do myself and that's all maintenance.
I did clean the MAF. No filter oil on it. I have been cleaning and oiling foam filters since 1972.
I will change the fuel filter just because.
I will check the brakes but I think they're OK, no pull or anything like that.
PCV is loose and rattling good. Aside from that,whats to check? I will replace the PCV elbow though mine seems OK. I will check a couple plugs too.
I have heard that alcohol in gas affects economy and the requirements in California are always changing.
I did see the other threads where people are going through he same thing I am but don't see any common problems or fixes.
Thanks all.

 

When my front pass side brake was hanging up there was no pull in the wheel at all.