Auto Parts: check engine light, fuel vapors, hyundai accent

Question
1999 hyundai accent check engine light is on.  Auto zone checked and said it is BBEVAP CONTROL SYSTEM GROSS LEAK DETECTED.  GAS CAP IS ON TIGHT ..NOW WHAT?  PLEASE AND THANK YOU

Answer
    There are lots of other places that the system could leak.  You'd have to identify and trace all of the tubing in the evaporative emissions control system. looking for a leak.  But, if you have replaced the gas cap with a non-stock one, it might not seal properly.  Before I went gonzo tearing the car apart looking for the problem, I would go to the dealer and buy a new gas cap.  The way the system works is that, shortly after you start the car, the computer commands the fuel system to be pressurized, slightly, and monitors whether it can retain the pressure.  If it leaks down, that means there is a leak, which means that fuel vapors can get out, and the government says that's a no-no.  Truthfully, you can drive the car safely like this, but it's poisoning the atmosphere, and you won't be able to tell if something else goes wrong because the light is already on.  You may find that the dealer already knows the most likely problem, if it is common to a lot of these models, and may be able to steer you in the right direction.  But, start with the correct OEM gas cap and go from there.