96 concorde idleing rough

I have a 96 Chrysler Concorde that is idleing rough. My car has 70,000 miles on it and has had regular oil changes since it was purchased new. I changed the spark plugs and noticed several plugs had oil on them. :banghead: Since the spark plugs did not fix the rough idle problem, what else may be the problem? Should i be worried about the oil on the spark plugs? If so can I expect expensive shop bills in the near future? Thank you in advance to any information provided.

Blown intake manifold gaskets!