Catalyst System Efficiency Below Threshold Bank 1 and 2

Possibly the oxygen sensor.

Cheers,

Dale

I should mention that this is a 1997 Ford Taurus with 68,000 miles.

============================ I think that car only has 1 cat and one sensor monitoring it. So it most likely needs the 1 cat to fix it. Jusy FYI, it wont hurt a thing to drive it other than our air. :)

I had this problem with my 1996 Tbird 4.6 at ~120k miles (now at 145k). Mine didn't both start acting up at once though. When #2 started acting up, I just kept clearing it and it was ok for about 10k-15k the first time. The milage between problems decreased until I was resetting it every day. I then started noticing that #1 was acting up. I took it in to the dealer and they said it needed a new head pipe assembly (contains a preconverter for each side of the engine and the main converter)- and they could get it done for about $1600.00 - well, needless to say, I jumped right on that- NOT. I had a cheap (not steel- a less durable metal - aluminum perhaps) one put on at Midas for about $950. Note: in these figures only $150-$200 is labor, the rest is for the part.

My car sounds like crap now- you can definitely hear the difference in the exhaust system- but at least it will pass inspection and it runs without check engine lights or the 02 sensors killing the engine.

Moral of the story - check everything else before you look at a new cat- they're expensive, and at least in my case, the car is not the same afterword.