I have a 2004 IS with 95k. I believe I have to fill up my tank every 270 miles. This is getting too expensive! I have checked my air filter and it looks fine. Anyone have an idea what I should look into?

Set appropriate tire pressure as defined on door jamb or owners manual
Get a general tune up including new spark plugs
Drive more conservatively (avoid jackrabbit starts)
Log your actual MPG for a while when you make these changes, rather than miles per tank.

^^ agreed. plus, winter gas yields less mpg..

Plus:
- make sure you change your oil regularly.
- maybe try different gasoline

eh, i get around that much too... what do other people get?

I get around 300-320 miles a tank on city/highway combo. Drive conservatively, and don't rev past 3.5k rpms.

Likewise. I usually hit the same. Sometimes right around 290-300 depending on how I'm driving.

I'm lucky if I get 300 on a full tank.

same here... maybe its the way i drive haha, last time i got about 325 on a full tank but that was from full tank to EMPTY like till the point where the car was gonna stop haha

I'm getting 11.7L/100km in middle of winter which is 20mpg city, directly in line with lexus specs. It's a heavy car, take your foot off the accelerator sometimes and let it roll. Takes a while to even start slowing down imo. As a side bonus, your brakes will also last longer. hahaha

I heard some ppl get better mileage when running synthetic, you could try that.

I average 18-19MPG (calculate every fill up)... Makes me want a commuter car

I get around 300-315 50/50 city/highway. Although my new job has me driving all city to work, so I get around 250 miles on 3/4 tank. In the summer I do better and all highway on trips I get like 375 out of a tank.

My EXACT thoughts two days ago, I filled up and calculated 19mpg...which included A LOT of highway (granted I was speeding, but still) and I just drive a **** ton for a college student.... I am definitely considering a commuter car like a 94-97 accord.

I purchased my '02 IS with 42k back in June and now I'm at 57k...fml.

Thanks for the information guys. I will get a tune up and also look into synthetic oil. I am also trying invested in a AEM cold air intake so we will see. I think I am going to get a old civic cause I want to keep my IS.

Get a JoeZ intake pipe unless you just want something you can hear.