I have a 2000 Plymouth Neon. It is burning way too much gas. I am wondering what is causing this problem. I only drive two miles to and from work. Two days ago I had a half a tank of gas, now its close to being empty. I haven't driven it anywhere else. What is wrong withmy car?

Several years ago I used a Neon rental car in L.A. I was shocked what poor gas mileage it got--something around 22 mpg. Chevy Cavaliers were not much better.

Here are some basic things to improve mileage:
1. Change spark plugs
2. Change air filter
3. Inflate tires to 34 psi
4. Add fuel injector cleaner every 6 months (e.g. Shell Regane or Chevron Techron)
5. Switch to 5W-30 synthetic engine oil (e.g. Mobil 1) and synthetic automatic transmission fluid (e.g. Mobil 1 Synthetic Multi-Vehicle ATF)
6. Replace oxygen sensor
7. Hook a scan tool up to the Data Link Connector and see if any codes are being thrown. Many auto part stores will do this for free. It may indicate a bad oxygen sensor or spark plug/coil misfire condition. This is a must, if you suspect something fundamental has changed.