oil in spark plugs

I have a 95' ford contour and it just started running terrible, backfiring, rough idling, dying at stops. So, i changed the plugs and whn i did 1 and 4 had oil on them, more on 4 than 1. What could this be from???

The car is running better, but still not up to par.:frown:

Oil i the combustionchambers is the problem. Can be worn pistonrings or something like that.

As SaabJohan said, this is caused by excessive oil entering the combustion chamber through worn rings and pistons, excessive clearance between vavle guides and stems, or loose bearings.

or loose bearings

um, which bearings can let oil into the chamber?