I would say something's wrong with the car. If you drive it gently and most of the miles are highway (i.e. better mpg), I would think you should be getting at LEAST 330 miles out of a tank. This would be about 30 mpg assuming an 11 gallon tank.

I've got a 96 EX (D16Y8 VTEC), and I do a mix of in-town/highway driving. I've got an LX tranny in it, which helps out my mileage, but if I get ONLY 330 miles out of the tank, I'm pretty pissed. Lately I've been getting 32-37 mpg, and that is very dependent on how hard I drive. I've hit 400 miles on one tank on a couple of occasions in the not so distant past.