I come to you in a place of desperation, I saved for a year to buy a nice car, I wanted AWD with decent gas mileage and already owned a Camry, so when I found this 2007 Lexus IS 250 AWD (150k M) I thought I was in for a good purchase. I Made an appointment at the dealership for one of those 92 point inspections, and had it looked over before I made the deal. The dealership raved at the amazing condition it was in, and said it had a "stored code" for O2 sensor. But the light wasn't on so it could have just been there from driving in unusual conditions, such as maybe a trip by the ocean, ( I live in ohio). I test drove it for around an hour, and made the deal. A week, maybe 2 later, the lights came on...   as Im sure u know, when the check engine light comes on, so does: !, check VSC, and traction control disabled. I was told it was catalytic converters, all 4 sensors, and cylinder 1 misfire. I Had both manifold catalytic converters replaced, and both airflow/o2 sensors replaced. ( $2200 ) then 6 spark plugs and a fuel cleaning ( $475 ). A week later the vehicle went into "limp mode" and was undrivable. The scan said, again, Bay 1 sensor 1. So I had it done by the dealer and sent the "faulty" sensor back for a refund. THat service was $750. A mile down the road,  the light came back on. Its now saying Bay 2 catalytic converter ( which is brand new). The dealership said its $2300 for the part not including labor, and he could not in good faith recommend the service, as I am clearly beyond the value of the vehicle. And there was no guarantee that would make the light go off.  I live in area with emission testing and cant pass with the light on. Im in over 10k and cant get it plated. The previous owner was a "platinum member" at the dealership, the sticker was still on the window. This can't be blamed on poor maintenance or abuse.