Tuesday, April 9th, 2013 AT 12:01 PM
My rear O2 sensors have been putting out low voltage for months which made the computer think that it was running lean, when in fact it was running extremely rich. I replaced both sensors and still had the same problem. I have aftermarket exhaust, headers, and CAI so I had my car dyno tuned. The tuner shut off the rear 2 sensors and I was finally getting decent air to fuel ratios. But a few days later I ended up getting the codes P0131 and P0151 (low voltage from my front 2 sensors). And I am still getting very poor MPG's. What would cause both sensors to fail at the same time?