Bring a large pot of salted water to a boil. Add elbow pasta and cook for 8 to 10 minutes until al dente. Drain and cool.

In a mixing bowl, whisk together mayonnaise, sour cream, red wine vinegar, sugar, and yellow mustard until smooth. Season with salt and pepper.

Rinse the cooled pasta under cold water, shake off excess, and add to the dressing. Gently fold to coat.

Dice celery, red pepper, and red onion. Fold into the pasta mixture until well combined.

Cover the bowl and refrigerate for at least 2 hours, preferably overnight, then stir before serving. Add more mayonnaise if needed.