I bought my 4runner off auction wrecked. Soon after I got it going, the charcoal canister vent valve started leaking and threw a check engine code. I diagnosed it and ordered an OEM charcoal canister. Now about 7 months later, it's doing exactly the same thing. I'm thinking I heard that a bad gas tank vent can cause gas to get into the evap system and kill it. But, I thought the charcoal canister was the gas tank vent, so I'm a little confused. Any help would be appreciated, thanks.