I am getting the same "Running Lean" code and I went to GM to get the t-fitting for the Throttle Body, because mine had a crack in it. GM is making me buy the WHOLE set-up with the tubing and everything for $23. They said they can't just order the t-fitting for me. And the guy said no one in NY state had it in stock. Are they taking advantage of me or does this sound feasible?