Hyundai Repair: CHECK ENGINE LIGHT, 2002 hyundai sonata, sonata 4

Question
I HAVE A 2002 HYUNDAI SONATA 4 CYL 71000 MILES ON IT TODAY ON MY WAY HOME FROM WORK THE CHECK ENGINE LIGHT CAME ON.  THE CAR IS SERVICED ON A REGULAR BASIS I KNOW I NEED TO TAKE THE CAR IN TO BE LOOKED AT BUT IS THIS A SERIOUS PROBLEM I HAVE BEEN TOLD A LOT OF TIMES THIS CAN BE JUST BAD GASOLINE OR A LOOSE GAS CAP.

Answer
A loose gas cap is a realistic possibility.  Bad gas, on the other hand, would tend to cause many more symptoms than just a check engine lamp.  If you think it might be the gas cap, make sure it's installed correctly and give the lamp a week to go out on its own.  If it doesn't, chances are good that the problem lies elsewhere.

If your car is running normally and the check engine lamp is not flashing, the issue is probably not serious.  In that case, it would be a good idea to have the car checked within a couple weeks if the check engine lamp persists.