Since i've had my truck i would only 10 mpg on a good day..I took my truck into a friends shop wondering why my mpg were so bad....Come to find out, whenever you switch your tires(not sure if its the tires or just the size) your computer needs reprogrammed...My computer was actually programmed for my 35's instead of the stock tires (not sure what size they are)...Reprogramming my comp to what my tire size was got me about 5mpg+.....So, if any of you have changed tire sizes and have done it yourself, i recommend checking your comp... This may improve your mpg if it has gone down due to a tire change....

 

I don't think you are actually improving the mpg. If the PCM isn't programmed for the correct size tires, the speedometer and odometer will not read correctly. Stock tires on a PCM programmed for bigger tires will give a higher speedometer reading and make the miles tick away faster than they really are. So you aren't improving gas mileage, you are now seeing what you've really been getting all along. Plus your speedo and odometer will read correctly.

Best of luck!

 

Need a little help here with re program, I have a 2500 gas 4X4 and of course my milage has decreased but my shift points are all over the place. What program is recomended for the dodge and will it help the shift points. I plan on start using it to pull my travel trailer and dont want to do so until the shift points are taken care of so I dont ruin the transmission and stuff. Thanks to any who can help and if any better advice I sure would appreciate

Jim Williams

 

Big Jim, You would get a better response if you went back to the 2ndgen forum and started a new thread so everyone could see it instead of having it buried on this thread. Highlight your text, right click, copy. Go back, post new thread, Type in a subject line, tab, right click, paste. This will get you on the main subject list.

 

You will need to go to a dealer to have it done, unless you know someone with a programmer.

 

i doubt it just changes the speedometer reading bacause after i got the chip tuned to the tire size settings i now have alot more torque in the mid

 

Yup, you've changed your effective final drive ratio. I get wicked off-the-line acceleration when I put race rubber (extremely low profile tires, non-DOT) on my Neon, but I hit the RPM limiter a lot faster (real speed vs. indicated speed). Same thing. I realize it's not exactly straightforward math, but it's how things work.