If your CAI was causing a problem, you would be lean in both banks. Since you are only lean in one bank I might suspect a bad O2 sensor. Before replacing anything, I would check to make sure the UIM gasket is OK. Lean in one bank and rich in the other is strange.
Have you ever remove the UIM? Might also check the secondary linkage to make sure the different sides are connected and working OK.
So exactly what were the codes they read?
