In a large bowl, combine potatoes, eggs,onion and celery; set aside. Place bacon in a microwave-safe bowl; cover with a paper towel and microwave on high for 2 minutes. Stir. Microwave 3-4 minutes longer or until the bacon is crisp, stirring after each minute. Remove bacon to paper towel to drain; reserve 2 tablespoons drippings. Stir sugar, flour, vinegar, salt and pepper into drippings until smooth; gradually add milk. Microwave on high for 5-6 minutes, stirring every 2 minutes until thickened. Pour over potato mixture; toss. Top with bacon. Serve immediately.