How many miles per gallon should my 2000 infiniti g20 give me?

It depends on several factors, starting with where you are driving. In city, on the highway, or some mix of the two. My boss has a 2001. I'm not sure of the exact mileage he gets, but on a straight highway run you should be able to do about 500-550 kms (300-330 miles) on a single fill. In the city, that will drop in half, or so, depending on traffic and weather. I always tell people to reset their trip odometer each fill, and see how far they go. The first sign of things going awry is the mileage on a tank drops. The other thing is, depending on the mileage, replace your O2 sensors. They make a huge difference to economy, as well as protecting your catalytic converter.

Gasoline. EPA Fuel Economy. Miles per Gallon. Regular Gasoline. 23