Hopefully it's just a spark plug. I had that problem... my first step was to replace the spark plugs when I realized that my valve cover gasket was no longer rubber but hard plastic that fell apart in my hands. I replaced that, hoping that it was the problem (my plugs were in great shape). Nope... it was a blown head gasket. I ended up getting a new (ok, lightly used) engine (wasn't really worth fixing a +250k mile engine). Have you noticed anything weird going on with your coolant or oil levels? If not, it's more likely that it's just what witeshark said.
Last edited by BeachBunny; 08-08-2009 at 10:01 AM.