Preparation - In a medium saucepan, combine the steak sauce, tomato sauce, onion, vinegar, syrup, vegetable oil, chili powder and pepper flakes. Heat to a boil over medium heat. Reduce heat and simmer for 5 to 7 minutes or until thickened. Prepare a charcoal or gas grill for use. The grilling surface should be about 8" above the coals. Spray the grill rack with non-stick cooking spray. Place the chicken pieces on the prepared grill, over indirect heat, and cook for about 35 minutes, turning occasionally. Baste the chicken pieces with the sauce and grill over direct heat for an additional 10 minutes per side, basting frequently with additional sauce.