Just went on a longer trip...low and behold, the car only used 1 quart in 650 miles. This is significantly better tha 3 quarts in 1000 miles however it still is unacceptable. I don't know why this happen. Thanks to the new forum on mechanics, I found a great shop in the DC area. He changed my oil and put in 20W50 and wants to see how this works out on on the next trip. To anyone-does this seem like a logical approach?
1989 420 SEL