leave it. ,my chechlight has been on for two month and nothing happened! do not worry about such thing. Little problem with your car so fix it when bigger problem occurs. Examing such problems need 50-70$, fixing some problems relate to checklight on usually 100-200$. Think about it.
there are so many reason to cause Check Engine light on, I think you better send your car to garage to check it out. Sometimes it might be small problem, but sometimes it might be a warning before big problem occurs. You better check it out.
no problem. my Elantra 1996 had the check engine light on for 2 months, then went off. After half year, it went on again, and kept ON all this winter, but since June, it went off again.
IMO, unless your car has other problem, no need to worry.