Evap Cannister Vent Valve

I'm trouble shooting a few CEL codes (over the past year). They are all Evap related (P0441, P055). I also get the MAF code (can't recall which one). Below are all of the things I have checked or replaced.
Replaced the gas cap.
Replaced the Purge Solenoid (the one up front under the engine cover).
Replaced the MAF Sensor.
Replaced air filter.
Toyota replaced my fuel pump a year ago.
Toyota replaced my O2 sensors (they were throwing parts at this thing).

I used a smoke machine last summer and there was smoke coming out around the filler neck (thought it was the gas cap so replaced that) but still getting leak codes and they went from small to Large leak (P0455).

Truck a few months ago would start up after filling with gas very rough (would take pumping the gas a bit a few times for a start). Now it does this nearly every start (leak must be getting bigger).

My question: I think I'm down to the charcoal cannister or the VENT Valve. Does anyone know the best way to test these? Also, is the vent valve solenoid sold separately from the charcoal cannister? I called Toyota Parts and asked. The guy had no idea.

Thanks everyone!

 

Seems like you're dealing with persistent Evap codes. To test the charcoal canister, try another smoke test, focusing on the filler neck area. The vent valve solenoid is usually sold separately, but it can vary by your car model. Check your parts catalog or ask a local auto parts store for details.

 

Did you replace the filler neck? Mine was leaking and I replaced it with the evap canister no issues

 

I have not replaced it. Did you have a leaking cannister? I'm trying to avoid a new cannister as they are around $700. Working my way in that direction though. I just can't find vent valve solenoids online for sale that are separate from the cannister.

 

I did the filler neck first and that fixed one of my codes. I snagged a used canister from eBay for much cheaper. The valve on the canister can’t be ordered separately I looked.

 

Thank you. This is exactly what I needed. Just couldn't find it separately. I'll start with another smoke test and see if I can tell where the leak is.