mix first four ingredients together and rub on all sides of roast. Brown roast on all sides in the oil.

Place roast in slow cooker. In same pan add the half cup of water and vinegar. Bring to a boil scraping up browned bits from bottom of pan. Pour over roast and cook on low 8 to 10 hours.

Remove roast and cover to keep warm. Put 1 1/4 cups of juices in saucepan, add water if there is not enough juice. Mix corn starch with sour cream and add to boiling juice whisking until thickened. Serve as gravy.