I understand that a bad O2 sensor can destroy the CAT. Is there anything that can destroy the O2 Sensor - bad fuel pump, etc.? Keep going back to the beginning. I am trying to trace the steps why an O2 sensor failed. I recently replaced the CAT a month ago. Then the power stage went a week later. I understand that can damage a CAT.

So now I have to wonder if the new CAT has been destroyed by the power stage. I see no point in constantly replacing all these parts, of there is something killing them that I am unaware of or should be looking at. I a starting to learn that asking why something fails is very important. Far too often, I am learning, that the quick advice I am getting on replacing these parts has not at all been thought out very carefully. Now I am back at square one again with having to replace these things twice - Thank you. Bruce