Mitsubishi Repair: 1995 Eclipse, valve cover gasket, worst case scenario

Question
My 1995 eclipse started running bad, I found fresh oil in the #3 spark plug tube.  I ran a compression test and all cylinders are within 5% of each other. The valve cover gasket is only a few months old. Could the oil be getting into the cylinder and making it run bad just from the valve cover gasket?

Answer
Larry,
Oil leaking into the cylinder is usually caused by oil getting past the valve cover gasket.  Double check the torque on the valve cover bolts to be sure they are within spec.  Over torquing can also cause a problem if it squishes or rips the gasket.  You may also want to remove the valve cover again and check for any minute fractures or cracks in the covers.  These valve covers are known for cracking pretty easily when over-torqued.  

The worst case scenario is if there is oil leaking past the piston ring and getting into the combustion chamber.  But that would usually reveal a compression loss and you already checked that.  So check the valve cover and gasket, and make sure everything is torqued properly.
Good luck!