Hi.Anybody know what i can do with my horrible gas mileage?I have 2003 dodge ram, 4x4, double cab 4,7 l, V8.I know when i buy that car i have around 14 city and 17 highway.After 2 years my mileage was around 12 City and 15 highway with stock 17 inch wheels.I change my stock 17 wheels for 35x12.5x18 in june 2010.But now i have around 8 city and not even 10 in the highway.I know that tires make horrible mileage but like that?I have K&n filter and i change my spurk plugs and install some stupid chip from Ebay for 30 bucks for better mileage and nothing.I use every day remote starter,warm my truck.But anyway i think something is wrong.What else i can do find out why my truck cost my $ 700 every months for gas?Can i uninstall thay ebay chip?Or change fuel filter help me?And one more question what psi you recommended for nitto mud grappler 35x12.5x18?Please let my know if you have some idea.Thank you

 

i think you answered your own question... one reason youre getting bad gas mileage because you warm your truck up everyday.. your trucks running but not moving so you guessed it bad gas mileage

 

Around 50k miles? check your egr valve. I just replaced mine and it was pretty dirty.

 

First of all, take out the ebay chip, you are doing long term damage to your engine.

Secondly, not only are you running 35" tires, but you are running 35" MUD GRAPPLERS, one of the most aggressive tire tread patterns on the market. Of course you are going to lose major fuel economy.

There is an old saying that says "you wanna play? you gotta pay".

You initial small drop in mpgs was probably due to lack of maintenance. Dirty EGR, throttle body, etc. But the major drop is lift/tire related. Ain't no way to get back more than maybe 1-2 mpg unless you go to a less aggressive tire. The only real way to get back to where you were is to keep up on the maintenance and drop the truck, go to 33" or smaller, less aggressive tires...

 

When you added the bigger tires, did that chip from ebay compensate in your ECM for the larger diameter(circumfrence) of the new bigger tires? You could be covering more ground than shows, but with bigger tires they rotate less per mile showing worse gas mileage than you are really getting.

 

This is also true, if he's never recalibrated his speedo after the tire change, he's actually getting better fuel economy than his overhead would be showing. But even if traveling at 70 mph for an extended period of time and assuming going from 32.5" to 35" tires, he's only going to show about a 1.2 mpg off. In reading his original post, the 1 mpg or so from speedo calibration isn't his major concern...

 

The warm-ups are killing your mileage. The chip was useless from the get-go, and those tires are not helping at all. You are getting better than you think, due to the tire diameter change.

Do you have a GPS? You can use it to figure the difference between the speedometer and odometer and what you're actually getting. My odometer is 4.3% low due to larger tires. I add that to the trip odo when I'm figuring my mileage.

 

Thanks guys for your help.Im gona remove that chip today,but i try find something about that egr valve and i dont think my dodge have one.I try find egr valve online and nothing.Just from year 2004.I try fix my speedo but dealer want my truck for half day so i just using my gps.Diferent with my 35 nitto tires is 5 miles per hour .If i drive 50mph actualy speed is 55mph.And can you help my with that psi for my tires?What tire psi is best for this tires and truck and for good mileage.Thank you.

 

i got 35's on mine i run 40 psi in the summer and 45 psi in the winter

 

ran my 37" Nitto Mud Graps at 35 front and 32 rear and rotated every 3000 miles and I got 50,000+ miles out of them. I run my Super Swampers at the same psi. Only time I run more is if I am going to haul a lot of weight for a long distance.