On #1, from your description it sounds like the cap, although on mine the recurrent CEL tripping was traced to a faulty inlet/filler tube. It was fixed under warranty, so I don't know what the cost would be. If you know someone else who has a Contique, you could try their cap to see if you still get the play when it's tightened; if so, I'd guess the filler tube was the problem.
