Gas Mileage Help

So I drive 2015 Toyota Tacoma TSS 4 x 4. When my truck was stuck I was getting about 15/18 mpg. Then I got New 17 inch you hostage wheels and bigger tires, 285/70 R/17, my gas mileage drop to about 14/17 MPG with my old wheels strapped down in the bed of my truck. A few days ago I decided I wanted a new Flowmaster muffler with dual exhaust. Currently I'm driving down to Texas from Mississippi and I just gassed up and I did the math and I got 11 mpg highway. Does anybody know if my new Flowmaster with dual exhaust pipes is the reason for this significant drop in gas mileage?

 

Are you compensating for the bigger tires when figuring mileage. Your current tire has about 7% greater circumference compared to factory tires. Meaning your odometer is reading about 7% less. If your odometer is showing you drove 300 miles, you actually drove about 321 miles. You're probably getting better fuel mileage than you think.

That would partly explain the drop from 15/18 down to 14/17. I have no clue why you are suddenly getting only 11 mpg hwy.

 

So I've had a very notable loss of 1-2mpg's since it got cold. About the same time I switched to 8" wheels instead of the factory 7" wheels.

Early morning drive TO work when it's cold my MPGs showing on my meter are much lower than my drive home. All that being said though my Fuelly account tracks my MPGs and it's noticably dropping the last 3-4 fill ups.

The change to 17" 285's isn't without side effect though!!

I used to get 19-20MPGs over all with just a K&N Air Intake mod.

After adding skids, aftermarket wheels, and cold weather I'm doing about 17MPGs now.

 

Thanks Marshall that makes so much more sense now. My next question, is there a way to re calibrate my odometer to compensate for the bigger tires?

Kyitty, that's one of my next mods is a k&n cold air intake.

 

From experience I can tell you the only difference is... loud. Over 3k RPM is loud.

 

Fill your truck with 91 or above and the-check. Made a difference in mine.

 

Noisemaker. Save your money.

 

On a recent road trip I set my cruise control at 60mph at left it for almost the entire trip. 24.7mpg I got that day, and thats with the 4.0L V6. If I stomp on the gas my mpg will go way down. On average I get about 17/20mpg.

 

I agree. I've considered removing mine but I don't want to deal with it. Personally I found it to be a PIA to install.