have evap check eng. lite.where can I find an aftermarket charcole filter . on 1998 Toyota Corolla

I've changed the valve on top (engine forgot name) 100.00 lite still on.the gas cap started to get real hard to get off.had to use 2 hands, when I took cap off no air came out ? the cap is new. It would start geting hard to take off after I had used a 1/2 tank of gas. HELP PAUL

Asked by for the 1998 Toyota Corolla
could be vac hose leak also seek diag and est
hi,thanks but I don't need a repair shop I need the charcole filter itselve. the dealer wants $300.00 for one. I'd like to find one on line paul.