As the stickie here for a 1999 Corolla's fuel economy shows, your Corolla has an EPA fuel economy rating of 25 city and 33 highway, with a combined average of 28 mpg -
http://www.fueleconomy.gov/feg/Power...la&srchtyp=ymm
So if you're getting 25 mpg combined, that's not too bad at all, especially if you're doing a lot of stop and go driving. 25 mpg is only 1 mpg lower than the EPA city fuel economy rating. Plus, when the EPA completes these fuel economy tests, they are not using winter blend fuels, (as we are now), which reduces the fuel economy about 10% or more.
Many people fill up the gas tank, drive their car until the gas tank is getting close to empty, then fill up the gas tank and dived the miles traveled by the gallons used and they think that is the fuel economy of their car and it really isn't. This method only shows the fuel economy of
that tank of gas only. That is not an accurate way to calculate the average fuel economy of the vehicle, as that method throws in all sorts of uncontrolled variables such as stop and go driving, head winds, different terrain's, etc.
The EPA fuel economy ratings are calculated by using a test track with variables controlled so they don't skew the fuel economy test results and accurate fuel economy averages for a given car can be reached.
Is your Corolla having any problems with the way it is running?
Tires can have a huge impact on fuel economy and can be the cause of wide variations from car to car. Some tires are very good on fuel economy and others not so good.
