I had to replace my o2s earlier this month and i also droped some water on the opti wile bleeding the ratyader. Now i am getting very light shuddering at idel and some times at part throtle, at first i thought crap the water killed the opti but it got better after i drove it around on a hot day.

but still has the shutter just barley enuf to notice most of the time
now i am thinking maybe the rich condition caused me to foul a few plugs if not all of them when i pull them tonight what should they look like and what should i look for BTW they are NGK 55's

 

they should have a nice even tan color to them.....if your plugs are black(rich) or white(lean) it is probably something that happened when you had the crappy o2's in

 

If they look ok, replace them. If they are fouled, correct the problem and replace them. I.e. replace them while they're out.

Apparetnly you are running coppers which "should" last for around 15K. Switch to plats or iradiums if you don't like changing plugs.

Check your gaps at .050 NA. JMHO