Trim fat from meat. If necessary, cut roast to fit into a 3-1/2 to 6-quart slow cooker. In a small bowl combine caraway seeds, marjoram, salt, and pepper. Sprinkle evenly over meat; rub in with your fingers.
In a large skillet brown meat on all sides in hot oil. Drain off fat. Place meat in slow cooker. Add water to skillet. Bring to a gentle boil, stirring to loosen brown bits from bottom of skillet. Pour skillet juices and vinegar over meat.
Cover and cook on low-heat setting for 8 to 10 hours or on high-heat setting for 4 to 5 hours. Remove meat from cooker; keep warm.
For gravy, pour juices into a large measuring cup; skim fat. Measure 1 1/4 cups juices, adding water, if necessary. In a small bowl combine sour cream and cornstarch. In a small saucepan bring cooking juices to boiling; reduce heat; stir in sour cream mixture. Cook and stir until mixture is thickened and bubbly. Cook and stir for 2 minutes more. Slice meat; serve with gravy and, if desired, hot cooked pasta.