My 2000 Tahoe started to run real slugishly after a few miles i got check engine light with P0131 and P0420. I suspect it is one of my O2 sensors but my question is which one will it be I have 2 forward of the cats and one behinde the cat is there a way that i can test them before replaceing them?

My 2000 Tahoe started to run real slugishly after a few miles i got check engine light with P0131 and P0420. I suspect it is one of my O2 sensors but my question is which one will it be I have 2 forward of the cats and one behinde the cat is there a way that i can test them before replaceing them?


this appears to be a driverside lean condition....its your job to investigate the cause...intake manifold???

if you end up replacing the O2 sensors, check on amazon.com. i ordered delco O2 sensors from amazon and payed literally half price compared to gettting them from the dealer. and yes, they are ac delco, same part # that the dealer gave me when he gave me the price on them.