i think there might be a problem with the truck. u had been getting 16mpg just driving around and 14 or 15 towing. on my last trip i got 10.5mph over the 1200 mile trip. this just doesn't seem right to me and thought maybe somethings going on. my temps were at a stady 600 degrees post turbo.

would an air restrictionbe causing this? i am currently running a drop in k&N airfilter.

any help please

 

10.5 empty?

 

the 10.5 is with the trailer on. and that same exact trip with very similar weight has always averaged about 14-15 before

 

Hmmmmm. That's a drastic change. I have a few ideas: fuel filter? Air cleaner? Bad fuel? Head wind (even with a strong head wind, my truck pulls the same, just uses much more fuel). I know you probably already thought of that stuff. Sorry I can't be much help.

 

anybody???

 

Do you have gauges?

What was your boost at?

Is this an isolated event...or happening all the time?

I won't ask the obvious questions, because I'm sure you have them covered...or you wouldn't be asking

 

i do not have a boost gague hooked up yet only the egt.

and its bein stady like this for a little while

 

Check your hose clamps and boots from turbo to intake, possible boost leak. Also clean the IAT/MAP sensors.

 

14-15 is pretty high towing. How heavy is the trailer?

 

I'm thinkin' boost leak/loss of boost somewhere...

Check all your boots and fittings...even try soaping them and start the engine.

I'm no expert...but get those gauges hooked up while you are in there!

 

I had something similar happen to me. I usually get around 19 mpg in town, and out of the blue, started getting low 17's and high 16's. I checked everything I could think of and read about with no luck finding anything. I had just changed my fuel filter 2k previously, and the air filter looked good, but I figured I'd start with the basics. I changed the fuel filter (which loooked fine) and the air filter, and my mileage is back to normal. Neither the fuel filter nor the airfilter were due to be changed, and they didn't look like they needed changing, but that was my solution, and has been fine ever since.

 

If I'm pulling my car hauler, (7500 lbs., 26 ft. and the aerodynamics of a phone booth) 11 is about normal through a mountainous area. I can drop it into the 9's if I lean on it.

 

that was proably towing 13 or 14k but i have reguaraly towed 20k and never had a drop like this

and thanks i will check for boost leaks

 

i tow 18 to 26k and never got over 10 anD dont even get over 12 towing my flatbed empty and it only weighs 8k dont see how you could get 14 towing anything heavy.

 

I have never been above 13 towing 8500lb camper. Usually 9 - 11 running 65. The 13 was running 50 - 55 through the mountains.