Bad mpg

[READYMAX]

I have a Generation 3 4x4 stock truck now. I get around 13-14.5 mpg everyday. Sometimes if I drive for 2 hours straight it'll go up to 16-17 mpg according to my computer. I was wondering if I took off my muffler or did something to get better mileage. The dealership hooked it up and said everything was fine and gave it updated codes or something. I run 285-75-R16 tires. I didn't know if this was common for these trucks. Also, what's up with the fuel tank only being 20 gallons??

[KEVINL]

Have you adjusted your speedometer to account for the larger tires

[MattZ71]

I have a Generation 3 4x4 stock truck now. I get around 13-14.5 mpg everyday. Sometimes if I drive for 2 hours straight it'll go up to 16-17 mpg according to my computer. I was wondering if I took off my muffler or did something to get better mileage. The dealership hooked it up and said everything was fine and gave it updated codes or something. I run 285-75-R16 tires. I didn't know if this was common for these trucks. Also, what's up with the fuel tank only being 20 gallons??

well, a 4inch turbo back exhaust will help mpg's, and if you go with a small programmer in the 50-100hp range and you drive good, you should see 1-3mpg better depending on driving conditions, 285/75 are pretty common on the trucks as well

and blocking the egr i recommend, our vendors have special deals that included a exhaust system, programmer, blocker plate, and intake all in one bundle....

[blksmok]

I have a Generation 3 4x4 stock truck now. I get around 13-14.5 mpg everyday. Sometimes if I drive for 2 hours straight it'll go up to 16-17 mpg according to my computer. I was wondering if I took off my muffler or did something to get better mileage. The dealership hooked it up and said everything was fine and gave it updated codes or something. I run 285-75-R16 tires. I didn't know if this was common for these trucks. Also, what's up with the fuel tank only being 20 gallons??

Have you adjusted your speedometer to account for the larger tires

Good point Kevin. If the speedo has not been recalibrated to account for the larger tires, your odometer will be wrong as well meaning that you are actually traveling further than you think when calculating mileage vs. fuel usage. Also, the displayed fuel mileage can be a ways off. You should hand calculate to get an accurate mileage report, but this can only be done if the speedo/odometer is correct or you are using a GPS unit for actual distance traveled.

I'm assuming you've done the usual things like check tire pressures, and air filters etc.

[READYMAX]

Can the dealership adjust my computer stuff for my tires? Also, I don't want a loud exhaust, I thought about just takeing out my factory muffler. But does anyone know why they made the motors stronger that year and the fuel tank smaller? I mean come on now!

[MattZ71]

Can the dealership adjust my computer stuff for my tires? Also, I don't want a loud exhaust, I thought about just takeing out my factory muffler. But does anyone know why they made the motors stronger that year and the fuel tank smaller? I mean come on now!

not sure on the dealer, but they probely can, you can get a turbo back 4" exhaust with a muffler.....

[blksmok]

Can the dealership adjust my computer stuff for my tires? Also, I don't want a loud exhaust, I thought about just takeing out my factory muffler. But does anyone know why they made the motors stronger that year and the fuel tank smaller? I mean come on now!

They CAN adjust for tire size, but whether they will or not is another question.

I have a 4" MBRP with muffler and it's not loud. At WOT, you hear it more, but under normal driving conditions, it's not loud at all IMO.

Your fuel tank should be 24 gallons in a short bed truck. Still to small IMO. One of the best mods I did to my truck was put a fuel tank in the bed. On my shortbed truck I put a small 37 gallon. It didn't take up much space and it was awesome on trips and such.

On my long bed I have a 60 gallon tank. I just got back from a 1800 mile trip that I did with only one stop for fuel. ( I think I could have made it the whole way but I didn't want to push it ):h)

[DWRAT]

I just got back from a 1800 mile trip that I did with only one stop for fuel. ( I think I could have made it the whole way but I didn't want to push it ):h)
That's only because you have a nice bed cover on your truck.):h

[qulinhunter]

Good point Kevin. If the speedo has not been recalibrated to account for the larger tires, your odometer will be wrong as well meaning that you are actually traveling further than you think when calculating mileage vs. fuel usage. Also, the displayed fuel mileage can be a ways off. You should hand calculate to get an accurate mileage report, but this can only be done if the speedo/odometer is correct or you are using a GPS unit for actual distance traveled.

I'm assuming you've done the usual things like check tire pressures, and air filters etc.

I use a GPS to track my miles and it says I go just under 8% farther than the ODO says I do (take your trip miles times 1.08 and divide that by your gallons from your receipt). As far as the Dic display, I go farther than it thinks, but burn more fuel than it thinks and it usually ends up within a couple tenths of my hand calcd figure. That's just my LLY computer though, yours may be different. Also, from what I've heard, if you go with a box programmer you can throw any mileage numbers the Dic says out the window.

[blksmok]

That's only because you have a nice bed cover on your truck.):h

It worked out great too, THANKS! :thumb:

I'm actually going to rig up a hoist in the garage to make it easy to put on and off so I can keep it for future trips without the trailer.

[DWRAT]

It worked out great too, THANKS! :thumb:

I'm actually going to rig up a hoist in the garage to make it easy to put on and off so I can keep it for future trips without the trailer.

Good idea, I ended up replacing my bed rail caps due to the cover scratching them up when trying to slide it off.

[READYMAX]

I got my computer reprogramed to my new tire size 285-75-R16 which happened to be the biggest tire size on the dealerships programmer. My MPG got better. Now I'm doing 14.5 - 16 around town, and 16 - 20 on trips to the beach. I still can't get no more than 300 miles per tank. The math doesn't add up though. I still think I have a 20 or 21 gallon tank. I would love to add an extra 5-8 gallons without to much customizing. I figured I'd let you all know how this went. Thank you for your replies.