In large kettle, cook onions, celery, and garlic in hot oil for about 5 mins. or until tender. Add tomatoes, sugar, salt, black pepper, and chili pepper (red pepper). Bring to boil; reduce heat. Simmer, uncovered, about 45 mins. or until desired consistency is reached, stirring occasionally. Add oregano and thyme. Simmer, uncovered, for 15 mins. more. Cool slightly. In food processor bowl, process sauce, 1/4 at a time, to desired texture. (Or, put sauce through food mill). Place sauce in a bowl set in ice water to cool quickly. Fill freezer containers; seal tightly, label, and freeze. Makes 3 to 4 pints.