I believe all these probs are connected. If I go up a fairly steep hill at highway speeds, the car will decelerate and start to lug a lot. At the same time I will be leaving a smokescreen behind me. At night when I park the car, there will be tar sands under the car. The rear main seal leaks, I believe because of hi crankcase pressure. The pcv valve itself is ok, there is some sort of screen/mesh under it that may be blocking the pressure. Have tried aerosol carb cleaner, seemed ok for a day. Will try more tomorrow. Runs well except for uphill and gets about 17 mpg, a lot for a car this big and old