Check engine light came on and went off and on and was of course worrisome, so,......I bought a manual. Not that outrageously overpriced, hard to use, monstrosity with no real page numbers from Hell company but a nice "good ol boy" book from Advance Auto. It, and Google searches and GM ng and finally my hands on solved the mystery.
Code 26 was set. Quad Driver etc.,etc, blah blah blah. Anyhow I did see and understand Vapor Cannister and I opened the hood and to my delight I immediately saw a real probable cause....a healthy black wire with about a half inch chomp out of it. Also evidence of some teeth chewing on the plastic AIR port on top the cannister.
I was delighted because I really was expecting that before I got it fixed, if ever, it would cost a lot in unnecessary replacement parts and possibly the humilation of going to a shop and paying big ones for an unending flashing evidence of the quad-biquitous.
Thought to cage the motor compartment bottom to keep em out. Is that an available product? Guess I'll do another Google "Engine Screen" "Critter Guard" or just buy some hardware cloth and sheet metal screw it in with big washers.
I enjoy this ng and appreciate the experts taking the time to help others.