Picked up a nail in drivers side rear tire yesterday.Jacked up rear of car last night ,removed tire and took it to be repaired today.Just put tire back on car,started up car and a very large cloud of blue/white smoke came out of the tail pipe plus some oil on the driveway.The engine was shaking so bad that i shut it off.Put car on ramps and found some oil dripping from rear exaust manafold[drivers side].My first fear was a blown head gasket,which i replaced 10,000 mis.ago when i rebuilt both heads.I let car sit for 3 hours, and the problem I HOPE went away.Could this have anything to do with the car being jacked up oll night,and some oil seeping into the cylinders??????