Update!

I went to a small local shop and got the inspection this morning (The CEL never turned back on) and it passed emissions. However, my rear brake pads were starting to get iffy and the metal started to scratch the disc. So, I'll have to do that and do the safety inspection again.

fredge, there is no noise.

Line7, I really am thinking it's either nothing or the O2 sensor. Thanks for the prices.

And thanks everyone for your help! I'll post back if anything changes.