2002 GPGT 3.8 vin K. I got a 420 code that won't go away. I've replaced both O2 sensors(generics from RockAuto and then with Bosch) and also the convertor, upper and lower intake gaskets with a new plenum and all the related gaskets. plugs/wires are recent. no drivability issues. I clear the code...It comes back in 10-14 days. A buddy of mine said he had the same issue with a Toyota at his garage. It took original dealer O2 sensors to correct.
Thoughts and Suggestions?
Edited by timwhite (05/05/13 10:46 PM)
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Thanks, Tim