O2 Sensor Problem

[elemgee]

My 94 SVX check engine light came on, and it was showing codes 32 (right hand side O2 sensor) and 37 (left had side O2 sensor). So I replaced both sensors with the ones by NTK. But I'm still getting an intermittent CEL code 37. I removed the left hand side sensor, checked all connections and reinstalled, but am still getting a CEL code 37. Any ideas what the problem could be? Not sure that this relates to the issue, but I recently replaced my MAF sensor with a new one for a 97 Legacy. Could I just have a bad O2 sensor right out of the box?

Other than the CEL light the engine runs and sounds fine.

Thanks.

Larry