[CREWZIN]

It's your oxygen sensor. The only problem is there seems to be a disagreement as to which one it is. There's one right in back of the engine (upstream) on top of the exhaust manifold and then there's one (downstream) on the right side of the CAT.

I had both mine changed out because I figured at 90,000+ miles, if one 02 sensor went the other wasn't too far behind.

I believe the code you have is for the downstream sensor. It can make the car run a little rough and mess up your gas mileage but it can't really hurt anything if you want to wait to change it out.