My milage is exactly like yours. Alot of people say that that the milage on the 2004.5's is alot worse, but I have not seen alot of 3rd gen trucks that get much better than mine. BTW, I get this milage w/ 315 tires. Also, teh trucks are very speed sensitive. If you can live going slower than 70, you will gain about 1 to 1.5 mpg for each MPH.

 

When I put on 'oversize tires' my milage did not change. Any loss due to more rolling resistance must be offset by increased engine efficiency at lower RPMs. My 315/70-17 effectively gear down my axle to 3.43 (compared to stock tire size 265/70-17 w/ a 3.73 axle).

 

I kept track of every ounce of fuel that my truck has seen in 70,000 miles. IS THIS TRUTHFUL ENOUGH??? My lifetime mpg (city, highway, towing, non-towing, etc.) is 19.3. In the summer, my HWY MPG is 22 (keeping it between 65 & 70 MPH).

 

Well, all I can tell you is that I used to see 17-18 mpg. Within the last 2 months my mileage has dropped off the charts. I'm getting 400 miles or less to the tank.

I'm not into the conspiracy theories too much, but I sure have read of a lot of folks who's mileage has dropped off recently. I'm starting to think it may be related to the fuel somehow. I can't really think of a good reason that an otherwise normal running truck suddenly sees the mpg go to the pot. I just bought a new transmission for my truck, but if I can't average more than 12-14 mpg then it's really not beneficial to keep this truck.

 

Maybe for your truck, but I can easily get 20. Just filled up and hand calculated 21 MPG for the tank, 60-65 MPH, and plenty of hills to climb around here. And THAT is a FACT!

 

Just had a road trip yesterday to Savannah GA. Ran with tailgate down stayed under 2k on the tach the entire trip, and only used ac second half of the trip. All highway mileage and running empty. My tires are worn down and only measure a little over a 1/4" taller than my factory tires were. Logged 459.2 miles and used 28.59 gallons of fuel. Overhead said 18.9, hand calculated only comes up to 16.06 No possible way I could have babied the truck more. Had my juice set on level 1 for mileage with the low boost smoke turned down. I don't see anyway anybody with an auto is getting 20+ to the gallon. My truck wouldn't hardly break 17 with bone stock tires and everything.

 

Again, leveling kit and and larger, aggressive tires are your problem. Just the leveling kit alone will cost you 1-2 MPG. Maybe it's the fuel in the SE, humidity,tire pressure, have you recalibrated for your bigger tires? Don't know, but I'm not making it up to make myself feel better, I check almost every tank. I'm totally stock with the stinker original tires, but they obviously get good fuel mileage. If I was getting 16 MPG at 2000 RPMs I would have to reconsider owning a diesel.

BTW, I don't baby it either, I drive it hard. To get 16 MPG (empty) I would have to be averaging at least 85 MPH. At 2000 RPMs I get 20, or slightly less, drops to 19 MPG at 75 MPH. If you were closer, I'd be happy to take you for a ride.

 

Best tank I ever got with stock tires and stock everything was 17.1 Everyone I know with these trucks get 14-16 regularly. My dad has a 6 spd and he gets 18-20 all the time, but everyone with autos just suck on mileage. I did notice about a mile to the gallon loss when I lifted and went up in tire size. You are right, I can't justify the cost diff in a diesel, but you just can't get that power from a gas motor. I think most of my problem is in how poorly effecient the tranny is.

 

When you had the stock stuff on was the motor broken in? I don't believe it's a problem with the auto tranny, unless you got a bad one. I have a friend who has an 03 auto and he has gotten 23 MPG, with the lower HP motor. I'm not averaging in any city driving either, except maybe a stop light or two. I'm talking about highway only.

 

The 03-04 were known to get considerably better mileage. I have a buddy with an 03 and he gets 18 all day long. The 04.5 is were horsepower went up a bunch, and mileage went down a bunch. I love my truck and wouldn't get rid of it for anything, but just wish the mileage was a little better. And no, my truck wasn't broken in good with stock tires. My brother in-law has the same identical truck to mine, year model, color, options, exactly except his is still all stock. He normally gets 16 around here and 18-19 on the highway. I guess this is what mine would do if it were stock, but then again, who wants boring stock!!!!!!!!! Like Tim the Tool Man said, MORE POWER arh, arh!

 

I have gotten 19 mpg (hand calculated) in mine when I had about 2,000 Lbs of rock in the bed. But then I did add 14 oz of Lucas in the fuel and I drove it on mostly flat ground on a state hwy at 55 MPH for all but 100 miles of my trip and even on the freeway I kept it between 62 and 65 MPH. When my engine only had 1500 miles on it I took in on a 4,000 mile trip with a small 1000 lb load plus vacation stuff and 3 adults and got 18.35 mpg for the whole 4K trip. So you see a stock truck with an auto transmission can get good fuel mileage, but then not all engines are the same.

 

getting the hard start TSB with all the latest computer programs should help you a great deal

 

When I first got it I had it reflashed for a bulletin on poor fuel economy. Has there been a newer better flash since? How do I find out about them? I really got bad when I first got it before the reflash, 11-12 around town stock. After the reflash it got better, but still not anywhere near what you all say you are getting. Again, I know the leveling kit and tires are hurting it, but I am only getting 13.5-14 around town, 16 on the highway, and 8-8.5 when pulling my 12k 5ver. I hate to think what my mileage would be with 35's or 37's.

 

i have a 2004.5 have a buddy who is a mechanic at the dodge dealler he told me to have the hard start and white smoke flash and it helped me with my fuel economy

 

I had my 2005 reflashed for hard start and white smoke and now it gets 2 mpg less. Do these rigs need the injectors cleaned at the dealer once it awhile? I'm getting 10 mpg with the camper on on the highway. Was getting 12 to 13. Not happy