My CEL flashed once while driving a few nights ago but didn't come back
 

My CEL flashed at my while crusing during decceleration a few nights ago. It quickly went away and never came back. I decided to check for engine codes today and it displays a code 28 (Knock sensor 2, LH), no other codes.

Could the knock sensor be going bad, did something random trigger the knock sensor, or could there be any other issues? Is the CEL supposed to stay on if it's a bad sensor? My engine wasn't running rough and did not feel powerless. It also idled normally.

I may be buying the pair of knock sensors from one of the guys selling them in the for sale forum, but before I do, should I just clear the code and see what happens in the next few days?

I have had that happen too. It has never come back on, so I have not worried about it. If it comes on again, you might want to check it, but if it doesn't, I would not worry about it now. jmho :)

It's probably the sensor going bad. My old sensors were both cracked.

I'll visually inspect both this weekend. I would think if either sensor had gone bad, the CEL would remain on or flash at me more often.

Thanks to both of you for the info. I'm going to hold off on buying the replacement sensors until I confirm they do need replacing (test and visually inspect them).