Okay guys I need some help! I've been watching this site for several months and have gotten some very, very good info and now need some advise. I think I have a handle on what's going on but I need other ideas in case what I think may be happening isn't. I have an '01 F350 4X4 CC w/6 spd manual and 3.73 gears. The best pre-mod empty mileage that I was able to get was 18.8. I left this weekend for a camping trip to the Ozarks pulling my 31' trailer. The day before we left I did the 6637 mod and started the DK dfa. On the way down I set the cruise at 2000 rpm and let her go! The hills didn't slow her down at all and I got 13.8 mpg at Warsaw, not as good as I would like to see but it's a starting point! During the return trip I could feel it struggling and had to downshift quite a few times. I took the same route with the same load except the return trip was about 15 degrees cooler. The only place I could find fuel where I was was Walmart (Murphy). I refueled at a local truckstop when I got home and only averaged 10 mpg!! I'm hoping it's either the DK loosening crap and restricting my fuel filter (I'm changing it very soon), possibly crappy fuel from Murphy or a combination of both. It's going to take several more tanks for me to figure this out but would like some other ideas in case my mileage doesn't come back up. BTW, I'd been watching the threads about the leaky DK bottles and mine dribbled the first time I filled my graduated bottle so I started looking at the 96 oz bottle and found a small lip (1/16th in or so) aroung the inside of the spout. I used a razor knife and trimmed that lip from the area that I wanted to pour from and Voila! no more dribbles of that stinky s**t all over my hands!

 

I would think to get 13.8 you had a very strong tail wind and the 10 you got is more of a real life number

 

those #'s sound right to me too.

 

Sound right to me, too. I tow a 31' 5er, 9k, and got 10.8 the last time I towed far enough to get a good reading.

 

Thanks guys, but that's not what I was really hoping to hear but it's probably true. That's not a whole lot better than the 3/4 Chevy Conversion van that I pulled the same trailer with before I got my PSD. If I get any better mileage later (I haven't checked solo mileage yet to see if that dropped also) I'll repost with updates.

 

How accurate is the overhead display for mpg and mpg left? For the last week, it says I am averaging 9.8 mpg towing or hauling nothing. I know that cant be right but my the gas gauge has been dropping at just about the same speed as the ole V10.

 

I don't have the overhead display. I top off the tank as full as I can get and figure with a calculator in my PDA.

 

It is refered to here as the LIE-O-METER. do not trust his device. This device was not made in china (as alot of good electronics are) it was made by the taliban as a device of terrorism.

 

Chayes - Thats pretty close to what I get while towing - 10.5 - 11.2 depending on grade and wind . Not a bad idea to change fuel filter after you run a couple tanks of dk thru. Now my mileage when not towing is 18.5 - 19.5 . Like somebody on here told me a while back, no matter what you tow its basically a wall behind you (resistance) and it doesnt make a lot of diff. if it weighs 5000# or 12,000#. I hoped for better towing mileage too but I dont think its gonna happen. Good Luck.

 

it was very windy in missouri this weekend and i myself was pulling my camper home and the head wind was bad! i used a lot of fuel!

 

Medhvac -Are you in hvac bus? If so comm or res? I do mostly res in St. Louis county area. Nice looking truck by the way.

 

thank you ,yes im in hvac i mainly do res but do comm sometimes i do installation i really hate service lol!

 

check for boost and exhaust leaks.