My Honda Passports check engine light flashes after Spark plug replacement.

What is your question?

In attempt to fix check engine light, I replaced spark plugs. Which by the way, how do I know If they're installed correctly? Also after tightening a spark plug to fix a high pitch chirping noise, I drove it around the block and CELight flashed a few times and reamained on. The old spark plugs had oil on them and there is a minor oil leak. I just want to fix the cheap stuff, not (catl converter god forbid). It sounds like a diesal