98 Intrepid intermintent smoke from engine

I have a 98 Intrepid with the 2.7L engine, just over 105K miles. The engine is producing blue/black smoke from the exhaust occasionally when idling. It clears out after about a hundred yards of acceleration. No codes are being returned from the ECM, plugs show no indication of oil useage, gas milage is good. The car runs great. There does appear to be some minor weapage from the rear area of the left head, but this may be from what appears to be a vent tube from the transmission. I have never seen this symptom from bad valve seals. Could this be the beginning of a head gasket problem. Have there been similiar problems with this engine? Plans are to do a leakdown and compression test next week. Any other suggestions would be appreciated. Thanks in advance for any ideas!