I just purchased this 2004 Elantra and I caculated the MPG today
It is ONLY 17.1 for the last 150 miles(local and I use 88 gas)!!
isn't it the claim MPG 26/34?
Is this indicate a problem in my car?
thanks.

 

First of all, 150 miles is not nearly enough mileage to get a meaningful number. Run several tanks before you freak out. Secondly, since they switched from MTBE to ethanol as an anti-emissions additive, the mileage seems to be a little worse. Also, this is winter time and winter-blend gas usually gives worse mileage.

And finally, don't drive the car like a sports car (if that's what you're doing). Drive the car like there's a raw egg on the accelerator pedal and you'll get much better mileage.