Does snow/water mess up spark plugs causing cylinder misfires?

I've been really negligent at scrapping the snow off of my car (99 Plymouth Neon) hood and a few weeks ago my car wouldn't turn. It made farting/pinging sounds. I tried it again in 15 minutes and it did. Today it made those sounds and shook and the check engine light came on. I took it to Autozone and its code machine said "Cylender misfire detected-Cylinder number 2". Well, an hour later the check engine light is off. What is up with that?