Pork and Peach Stir Fry

1 pound pork tenderloin, cut into cubes
1 tablespoon vegetable oil
1 onion, chopped
2 cloves garlic, minced
3 each green and red bell pepper, cut into cubes
1 (19 ounce) can peach slices packed in own juice
1/4 cup rice vinegar
2 tablespoons soy sauce
2 tablespoons cornstarch

Saut