I bought a 2011 GT six months ago. Idle has been high at 1000. Took it to the dealer finally and they said not to worry. The say they cleaned the throttle body and all is well. (NOT) Sure it idles at 700 now but I get a check engine light that codes as lean bank 1 and lean bank 2. Took it back and they told me it couldn't be remedied as long as it had the after market air filter (cone type like K&N but labeled JLT). They swear it runs fine on a stock set up they tried on it. BUT it ran fine for the last six months, what is different now? They say the cleaner throttle body lets in more air and I need stock filter to fix it. I asked how much. $800 in parts plus labor. None of this makes sense to me. How can a better air filter cause this? And $800 for a plastic box and hose! I feel like I am being lead to slaughter. Any suggestions?