thanks in advance to all brickers out there...S70 owner looking to help out a buddy with a newly purchased 1996 960 wagon...115k on the odometer, very clean overall, got a good price...my question..CEL on, pulled code, got PO422, Main Catalyst Below Threshold (Bank 1)...O2 sensor gone or going?...one of these(there is two I believe), was a replacement done at Midas(collective cringe) by previous owner shortly b4 the sale to my friend..read on forum that these cars are particularly sensitive, and to use OEM O2 sensors....any help will make me look the hero...