Found this site via a Google search & read quite a few threads. Like many of the participants here, I am looking for the best fuel efficiency I can coax from the 2006 Dodge Ram 2500 4 x 4 Off Road I purchased last summer. Originally, I had a 07 Jeep GC with the 3.0 CRD Mercedes model. I used the Jeep as a personal vehicle & to tow a small utility trailer GVW 3000 lbs. Last summer I purchased a Lance TT that had a loaded wt of just over 5,000 lbs & tongue weight of approximately 650 lbs. On a trip from PA to TN, GA, VA the Jeep did a nice job of towing & delivering approximately 14 mpg. On the second half of the trip the Jeep began to throw a 4 wheel drive system "needs service" code. After the first Jeep dealer in NC found nothing to fix & basically turned of the code the code again activated & the vehicle had to be towed from a campground to a second Jeep dealer. The issue turned out to be a minor part: front diff actuator for ther Quadra Drive II system.
Since we were planning more extended TT towing to mountain regions in CO, WY, etc , I decided to move to a more robust tow vehicle: thus the 2006 one owner FLA registered Dodge Ram 2500, 4 x 4 with 112k. The truck runs great, has good service history and looks to be well cared for. It is equipped with the "legendary" 5.9 HO Cummins Turbo diesel, 48RE 4-Spd Auto Trans & 4.10 Axle Ratio with towing package. It is a Laramie Quad Cab, 6.5' bed, running LT265/70R17E all season tires. I had new DynaTrac Ball Joints installed which, after a little sticky break in period, are tracking very well.
Initially I was relying on the vehicle trip computer for mpg figures. On rural back country PA roads with little stop and go and very conservative driving I would see 24 - 26 mpg figures reported by the vehicle computer. My computer on the 07 Jeep had always UNDER REPORTED mpg by about 2 mpg, so I was very happy. It looked like towing the trailer was providing 15 - 17 mpg depending on the terrain. HOWEVER, MY FREQUENT FUEL STOPS LED ME TO BELIEVE SOMETHING WAS A BIT OFF! TRY THE TRIP COMPUTER OVER REPORTING MPG WITH ERRORS RANGING FROM 5 TO 9 MPG.
Looks like my fuel economy basically SUCKS! Try about 15 mpg non towing rural driving & 11 mpg towing the 5,000 lb Lance Travel Trailer. While I can't imagine diving too deeply into the "sweet spot" rpm theory (sounds reasonable & well informed) I am driving with a "light foot" & have achieved excellent results with every other vehicle I have owned. I did replace the well cared for K & N air filter & may have noticed a little difference, but I'm at a loss to see how some of you folks are achieving the 23 to 25 mpg averages with a heavier 3500 Ram dually. ANY IDEAS???