Camry emissions trouble

[multistage]

Hello to all, new to the forum. My wife has an 03 Camry, 4 cylinder, with a check engine light on. Code is P-0446. I forget the exact definition, but I know it is emissions. As a Caterpillar mechanic, I don't use a scan tool, but after I took the car to a dealer last summer and they told me it was a 900 dollar repair (which I declined) and then nailed me for 100 dollar diagnostic fee, I bought a scan tool from my banker, the Snap On guy. What concerns me is that the car will occasionally sputter on initial start up, badly after fueling. The car has 112,000 miles. I recently changed the plugs (factory iridium), sanded the fuel filler tube sealing area (lightly), and replaced the fuel cap with a factory cap. I cleared the code and after a month it came back. Should I be looking forward to shelling out 300 bucks for a new charcoal cannister? I understand that there is no serviceable fuel filter on this car (that is WIERD!). Any input will be much appreciated. Many thanks.

[gdanaher]

Emission controls can be a royal pain. It looks like you've done your homework on this problem, but there could be others in your area capable of repairs mith price tags well below the dealer. I love dealer service. Don't get me wrong. They get it fixed and it is warranted by the manufacturer, but at some point you begin to see it nickeling you to death and you don' want/have the money to spend on stuff to get the light to stay off. Talk to your friends and shop around. Find a good repair shop that might even give you a free opinion about what they think the problem is. Might be the vapor canister or it still could be something else. Second opinions are worth a fortune/