Hey folks, got an interesting situation that has recently come up on my 2004 taco, w/ 3.4l.

Couple months ago I noticed a slight ticking wasn't loud and wasn't coming from the engine so didn't worry too much about it. Then couple weeks ago I decided to track it down and find out what it was. Turns out to be the evap OBD canister closed valve. No biggie figure when I get some other projects out of the way I'll look into this. Then couple days ago I come out to the truck and I can hear this thing ticking. No key in ignition nothing. Of course I'm up to my elbows in fixing a fuel pump on another rig. So I unplug it, noise stops, and I continue with my pump. Next day I put the key in the ignition and now there a ticking coming from around the gas tank. Figure it's probably the evap canister. So now I'm wonder what exactly is going on? Why is this thing ticking without the truck even being on? And why after unplugging it did the (what I assume) the evap canister start ticking? Any thoughts? What to fix first?