I seem to be using more fuel pulling my travel trailer. Up to this last trip I made I would get 13 to 14 mpg. I made the same trip got 10.5 to 11.5 mpg. My load was the same on both trips. What is my problem?

2001 4x4 2500 QUD cab 24 valve diesel auto trans. with a cab high Leer shell

The trip I noticed the drop in mpg was the same as other trips. I hold me speed at 60 mph. Weather was a little factor. I factored that in to my concerns.

 

It could be alot of things. 1) Winter blended fuel. Were all of your other tows done during Summer months? 2) IAT sensor could be going bad or could be dirty. 3) Speed. This can have a big impact on mileage. Did you tow faster than normal?
I tow a 9k 5th wheel and have averaged about 10mpg since I've had the truck. However, alot of my towing is on the interstate at about 70-75mph in OD and the wind resistance on my 5th wheel puts a major dent in my mileage. I found that my average speed picked up as I grew more comfortable with the rig and my mileage went down.

 

What year and engine in the vehicle.

That knowledge will better help the diagnosis.


phox

 

what about the overflow valve? not sure if thats in the 24 valve too or just the 12 valve.

 

k