I was going to say try O2 sensors.. Would recommend unless you just have a killer discount at a stealership or auto parts store to pick up your O2 sensors through Rock Auto.. Had CEL issues with my gf's LJ and ordered some through AZ and it was crazy high priced.. So I went on Rock Auto and ordered all 4 that hers had brand new NTK O2 sensors, as we figured out that they don't like Bosch sensors, and got all four cheaper then two of the Bosch sensors @ AZ... Just a heads up..