I've changed gas cap,EVAP canister, clear code, but still pops up. Is there a way to check for a fuel leak or any suggestions on what should I try next.
My car has an automatic transmission.
You should have a mechanic use a smoke machine to test the system for leaks. The purge valve may be leaking causing it to not hold any vapor in the tank at idle. If this occurs it will cause the Check Engine Light trouble code P0455. If you need some help with getting this fixed, contact a certified technician, like one from YourMechanic, who can diagnose your Check Engine Light and help you make the necessary repairs.