In a saucepan cook carrots, covered, in a small amount of boiling water for 8 minutes; drain well. Drain pineapple, reserving juice. Cut pineapple slices into quarters; set aside.
For sauce, in a saucepan combine reserved pineapple juice, vinegar, oil, soy sauce, cornstarch, sugar, and garlic. Cook and stir until thickened and bubbly. Cook and stir 1 to 2 minutes more.
Thread cooked carrots, pineapple, green and red pepper, and pork on four 12- to 14-inch skewers, leaving 1/4 inch between each piece of food.
Grill kabobs on an uncovered grill directly over medium-hot coals for 8 to 12 minutes or until pork is thoroughly cooked. (Or broil 4 to 5 inches from the heat for 15 to 18 minutes.) Turn kabobs occasionally and brush often with sauce. Makes 4 servings.