lately my car eats unbelievable amount of gas...
it eats like, more than v12 bmw 8 series, more than sts with northstar engine.
i don't even push the car often, my friends call me "granny driver."
my engine-oil change is a bit overdue, but only by 500 miles or so.
other than that, as far as i know of there's nothing else that might
cause such problem.
what do you guys think the problem is?
i'm going crazy thesdays because of this issue...

 

What are the numbers, Seung.

I've noticed declining gas mileage (from 27-28 avg to 22-23 avg) over my year+ of ownership, but I don't worry about it.

 

I've noticed my gas mileage varies not only with how I drive, but the kinds of trips I make.

For example, if I make lots of short stop-and-go trips, I'll average about 20 mpg.

If I make longer commutes, I fare much better.

Have you tried resetting the ECU?

 

hmm... yes, i know declining mileage is unavoidable as a car gets old, but, my case is somewhat different.
when i say it's crazy, it's crazy like you filll up the gas, and
about 10 miles later 3- 4 bars are gone... and that 10 mile is
easy, below 5 rpm, slow 10 miles...
then 3 days later i have to fill up gas again!
yes i did reset ecu too...
hmm... it really worries me.

 

Seung, that doesn't sound right.

 

Are you getting and driveability issues - black smoke from tailpipe, surging or hesitation?

A CEL?

Sounds like you may have one or more bad injectors, a bad O2, and of course, the infamous MAP, but you still have not rteally indicated what your mileage is.

Give us a tankful to tankful reading. Sometimes people change their driving habits, and this is changeover gasoline time, but what you are describing is way over the top.

 

Don't pay any attention to the bars on the display. They're very nearly worthless. Instead, reset your trip meter after your next fillup. Then during the one after that, record how many miles you drove and how much gas you put in. From that, you can calculate actual milage. If it's above 20mph, you're fine.

 

Seung,

Sounds like you're going to a gas station that isn't giving you 100% gas. Ever hear of those stories where gas stations dilute their gasoline? I hope thats not the case.

Other than that...I do not know what it could be.

I am surprised you guys get 26 mpg, I am getting at 16 mpg. I vtec about 5 times a day.

 

thanx for all the replies, guys...
i go to random gas station all around the town so i don't think
it's "diluted gas" problem...
Road Rage's info was helpful, even tho it kinda scared me.
i will try to measure my milage too, to see how it really is.
again, thank you guys...

 

Do you keep up with maintaining the air cleaner? Replace if stock, clean if aftermarket? Do you do any injector maintenance? Have you noticed your tail pipes getting sootier faster and blacker than it used to? Have you gone to tires that have higher rolling resistance? Pressures kept up? Done all the proper fluid changes for tranny, diff?
Mine is over 3 years old now and when compensating for the gears, I get about the same fuel economy as I've always gotten.