2011 G37 bad idle

[GTA]

My 2011 G37 is starting to idle bad it drops to 500rpm. But sometimes it’s good at 700. Also power is good than sometimes it lacks. Confusing!!!. I’m getting ready to clean both Throttle bodies and do the re-learn procedure , hope that works. It has 94,510 miles on it. Used obd2 scanner said something about EVAP. I can get around a car. Did my new rotors and pads, oil, etc. but when it comes to the heart of the car I’m like a blind man. I’m good at following directions from someone that can steer me on the right path, any help will be appreciated. I’m new to the site. Love my car but in the back of my mind I’m waiting for the dreaded Galley Gasket to blow. Thanks a head of time.

[G35007]

Your EVAP canister may detect a leak and needs to be replaced. its in the rear of the car between the mufflers behind the cover that's bolted in down there