dOES THIS SEEM OK TO YOU GUYS? I was hopeing to get around 9 but am only getting low 7's. I tow a Travel trailer that is 10' tall and 8' wide max loaded weight with full water and week worth of gear was 4900 lbs. I have a rebuilt tranny 3.73 gears new plugs air filter and fuel filter. Runs smooth and no other issues.

 

Kinda depends on the terrain & speeds, right?

 

I know a lot of folks don't beleive me, but I think that filling up with a higher octane gas makes a difference in towing mpg's.

How fast are you going? If you are driving 75 that would not be bad MPG.

 

That seems pretty low to me. I would think that the V10 should do better than that. Where were you towing and how fast? Were all of the tires inflated properly?

 

I got 9 mpg pulling my 10500 lbs. trailer.
Unless you are doing a lot of stop and go type driving something is wrong.

 

Thats more along the lines of what I was thinking. I averaged 9 with a 25' enclosed trailer tipping the scales at 9500lbs in an Expedition.

 

if your fuel filter is good check your MAF in the air intake tract. Might be dirty.

 

Ok another thread about fuel filters and gas mileage. Can someone PLEASE explain why they think a dirty fuel filter can lower gas mileage? With all i know this makes NO sense to me whatsoever.

 

Headwind? Hills? Avg speed over the trip are the three biggies that will make or break MPG on a SD. I can get 11 towing my 8000 pound fiver or I can get 8. Drive 62 and I get about as good as it'll do. Drive 70 and I lose at least 2 MPG. Drive into a headwind and I'll drop 1-2 MPG. Hills...the same thing.

 

ok, negligable head winds, towing 60 to 70 mph. No stop and go, all freeway (I-5).
Like I said.... filters are new and so are plugs. I always run Shell or Chevron from a newre looking gas station. I do use 87 octane. Any other info I can give to help make an informed decision?

 

It does seem low to me based on my experiences. I tow near twice the weight you do and have towed 5000 miles this year thru varied terrain (including Appalachians) and weather (head winds)...in those 5000 miles I always burned 87 octane and averaged 8.3mpg (sure some tanks were more and some were less...that is the average). How many tanks are you basing the low 7's on?

On the 87 octane...is that full petrol or some ethanol?...I found last year that when I ran the 10% ethanol cr@p I got really bad mileage.

Also with your 3.73's...do you lock out OD and just tow in 3rd? I also found when I had 3.73's...it actually ran better to lock out OD as there were almost NO downshifts that way...the V10 would pull very strong in 3rd gear up many good hills...at 65mph in 3rd I would turn 2700RPMs.

Do you have any oversized tires or anything?...I couldn't tell from your avatar photo...if you did upsize the tires...did you adjust your speedo...just a thought.

Another thing I can think of...are you carrying any weight in the bed to speak of and have you verified your weight via a scale or estimated?...I don't think the scale is important since you are only talking in the 5K# range...but more thoughts...

What about tire pressure...are they too low?

And my last thought...are your hubs locked for some reason?

Good luck,
joe.

 

Joe, Excellant questions. Tires are at full psi, Have not verified weights exactlly but are in the range... +-200 lbs. I do have a bed box but it is currentlly pretty empty(maybe 100 lbs total). I do think the fuel in WA is oxigenated at this time of year. I Just put on Warn Premiums and am positive they are "free". I use the truck to tow the trailer 90% of the time. Lets say the last 10 tanks towing have averaged 7.5 or so.

I do lock out OD IF the transmissins shifts more than once or twice in 5 minutes.

 

Have you checked the trailer?

Maybe it has a stuck brake, hub or bearing problem or even a bent axle that is causing excess "drag".

 

What size tires are you running? If they're not the size that the computer is set for, you'll notice it in your perfomance and milage when towing. Happened to me.

 

stock 275 65's "space savers" as the guys in the washington chapter call them.