My XJ 4.0 was running well until yesterday. On my way to work ran smooth. On my way home started to shake and run real rough. when I stop in gear the rpm drop down to under 600 and the jeep almost stalls. if I quick put it in neutral rpms are fine. Opened hood and oil is sprayed all over distributor and side of block. while also in the air filter compartment. I had this happen a month ago and I changed the pvc elbows and rubber grommets and vacuum hoses. And It went away. I have the CCV system for crankshaft pressure. Any one have any thoughts or leads?