p0456

I'm new here anyway, i have a code ( P0456) that i cannot get red of , it's upsetting me because it comes on when the weater is cold then i clear it then it won't come on at least coup of days then it will come on again. Anybody knows how to fix it, i changed the gas cap already, i would appresiate if somebody would tell me how to fix this code. thank you for everybody ....S.O.S....:banghead:

or have an ideal what to do....

Make,year,engine,mileage would be helpful.

it's mitsubishi eclipse 2003 gts
miles: 150,000

Try this - www.obd-codes.com/p0456