hey my 03 is having some issues...my engine light comes on from time to time...ive tried replacing the o2 but after a while it just comes back on. and just if it helps my a/f meter bounces around like a 5 year old on a sugar rush....whats the deal?

also i have the arc intake box..dont ask it came with the car...and i kepp sucking in moisture. any time you drive it in the rain it starts sputtering and sometimes stalls out and is a ***** to start....whats an easy fix to this. im open for all suggestions...