Jack_in_the_Box

my average mileage per gas tank is around 230 miles. i just recently got gears in january it never changed my driving habits and still averages about 230 miles on each tank. now all of a sudden i didnt even get 200 miles. my light came on with 2 bars on the meter and it was barely at 180. just filled up yesterday and a quarter tank is already gone. i've only driven 38 miles. usually after a quarter tank i've already clocked 60 miles. my CEL light is not on either. my driving habits like i said have not changed. i drive normally shifting at 3500-4000 rpms and every now and then i'll vtec here and there but not very often. i also bought my gas from a different gas station to see maybe if it were bad gas. other gas mileage effecting mods i have are a test pipe with a CEL fix ( 2 yrs) and a 02 ECU. my K&N drop in filter is still clean as well. the only things i can think of is maybe my 02 sensor is on its way out and my CEL will come on soon, maybe i need to clean my injectors to. is anyone else seeing there gas mileage plummet under normal driving?

e3opian

My girlfriend just asked if you've checked your tire pressure. I'm so proud of her.

FF2Skip

Damn Obama-nites!

Jack_in_the_Box

i've been meaning to check it, but honestly would my overall mpg drop 30+ miles due to that? my tires do not look any lower.

e3opian

You should know her better than that. Besides, I had the same problem when it turned super cold.

e3opian

That's what 8-9% difference? Lower profile tires don't show unless they're almost completely flat. At that point the car should be driving dangerously sloppy to let you know there's a problem.

FF2Skip

Sidewall stiffness hides a lot of pressure drop. And yes, it could definitely change your total mileage. Additionally, the colder air is denser causing the ECU to dump more fuel into the motor to maintain the proper A/F ratio.

These aren't necessarily the cause of the reduction, but are possible contributors.

Jack_in_the_Box

i thought that too but its just weird. it has been much colder the past few months than the last 2 weeks so i dont see why now it would start to dump gas like that.

tacocat

Junk in the trunk? E brake on? Using regular instead of premium? Dirty air filter? Low on oil?

Jack_in_the_Box

i barely have anything in the trunk (tools and spare tire are gone), e-brake isint on (all 4 calipers have seized on this car, i would know if it were the brakes by the smell), air filter is clean but i'll clean it again anyways, and i just change my oil about 400 miles ago using the same oil ive always used ( mobil 1 10-30 fully synthetic).