My gas milage has dropped down to about the lowest it has been ever since i had my car. I just had 18" installed so i know that might be a factor in it but i'm not to sure why it keeps dropping anybody hane any ideas on how i can build it back up?

 

Well, you may want to start by spelling MPG right in the title. So people know what the threads about. Then tell us what car. Then what Trans, Mods, ect. When did the change happen, mpg's always go down in the winter. Deffernet fuel blends, ect. More info needed.

 

i think any car with 18" lift would see a decrease.

 

I assumed he ment 18" wheels. But damn, is the Cobalt whell gap not enough?

 

The only engine mod i have is the gmpp intake and i have a 2009 ls stock transmission

 

winter gas? it sucks

 

What exactly are you getting? And you're probably just seeing the effects of winter mix gasoline.

 

well the wheels are gonna be heavier than stock so the milage will go down... and winter gas sucks, and most people so stupid things like let the car warm up for too long,

 

My milage was at 24 but it dropped down to 16. I normally fill up at shell gas station but ive been tryin exxon

 

16MPG? Geez.

Do you have a remote start? Is this completely city? How are you calculating it?

I got better gas mileage than that in my Isuzu Rodeo in the city, and that thing was a pig.

Joel

 

I just mostly drive around the city. I'm not much of a speeder and i've tried everything thing but i'm not to sure what much i can do

 

You just had 18s installed. Your odometer may be off due to the difference in overall tire height.

Simplest explanation for getting 16. I have a lead foot and get 19 - 20 out of my TC in the city.

 

what about spark plug age? bad gas? how many tanks of gas have you gone through?

 

My car does keep telling me to service tire monitor but i thought that was due to my tpms. could that be a problem on my odometer

 

calculate your mileage off of what a gps tells you for a tank and then lets see what you get.. getting 16mpg is literally almost impossible on a stock-ish ls. i would bet your just getting way "less" miles because your tires are larger

 

Tires being larger...sure, but i highly doubt he could be running THAT big a tire to make that big a difference. Just saying... Unless you but some blingy, quadruple chrome platted **** on there...and if you did, you deserve it.


So we will start by asking what size tire/wheel combo are you running,

 

my tire size is 225/40/18

 

well its about as perfect as could be. How much do those rims weigh?

 

^even that shouldnt make a massive difference.. clogged cat maybe? plugs? idk i just throwing stuff out there

 

He has an 09, almost impossible for any of that to be wrong...

..miscalculation maybe?

 

How are you calculating this? Don't go buy what it says. Calculate it yourself

 

IF hes going by his DTE (do LSs even have that?) his MPG will actually be lower. So if his DIC is showing 16mpg, its quite a bit lower

 

we could do some simple farmer math.. how far could you normally go on a tank compared to now (given you drive the same route from tank to tank) it could just be in your head lol

 

Hahaha, that is true. The DIC is worthless for MPGs

 

I get better mileage in my car... DAMN!