I’ve made an appt with my local shop to do just that as I don’t have a smoke machine. On my list of never ending tools lol. Whats got me is the rich issue had come up long before the evap code. I also had gotten a misfire and that turned out to be an injector so I replaced them all. I went after market denso of course but they were custom. Instead of 4 large holes (i have the lc9 flex) it was 12 smaller holes. Meant to atomize the fuel for a more efficient burn. After the swap at first everything seemed ok for a few hundred miles, the monitors had all come back no pending codes. Then its been reading rich off n on ever since and by off and on its narrowing it down to a reading that is out of norms and replacing the part responsible (ie MAF). As for the EVAP system as I said before the vent valve was done maybe 6 months ago and I did the purge valve solenoid about 6 years ago (that 1 gave me a specific code for failure i remember) and during my troubleshooting I had thought the canister might be the issue, but not being able to test it further I went looking elsewhere and so far pretty much everything else has been replaced in the fuel system except the canister and the pump (which reads perfect down the middle for recommended PSI range). I am REALLY hoping you are right and its to do with the canister. Ive never replaced 1 myself but from what I’ve seen its not too terribly difficult. The way it goes is if I can’t figure something out (and the local shop went thru it as well for the rich codes before even after the new injectors and such and couldn’t find anything obvious as all we had were both banks rich showing) then I bring it to them for diagnosis. If I can fix it then I do. If I can’t I pay them to do it.