I recently finished replacing the timing chains on my '09 as described in another thread. The car runs fine but I'm getting an active P2187 code for too lean at idle bank 1 and a pending P2189 code for too lean at idle bank 2. I didn't get these codes before the timing chains job. The manual mentions that the computer senses unmetered air entering the engine as from a vacuum leak. Could it also be an intake manifold gasket leaking? I didn't replace it when putting back the intake manifold.