Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance Air filter retainer clips - how important?

P1137 Lack of downstream Heated Oxygen Sensor (HO2S 12) switch, sensor indicates lean (Bank #1)

P0420 Catalyst system efficiency below threshold (Bank #1)

Doubtful that the missing clips are causing an O2 sensor problem unless the IAT is sending bad info causing the P420.
My guess is your O2 might be done. Cheapest fix reset the computer and see if it comes back.

The clips are there for a reason and you should replace them. Easiest way is if your close to an auto wrecker go pick some up.
The clips on my car look similar to alot of other cars so you should be able to get them anywhere. Just take the last one with you and match it up.