So a few months ago, my check engine light came on. I took it to a random mechanic, he said he scanned it using two different scanners, both giving him different codes, but the one common code they both gave him was for the catalytic converter.

He reset the check engine indicator, and it came back on again after 30 miles. But since then, it has been off most of the time, but comes back on occasionally. Any experience with this, anyone? Or at least some educated speculation?