Sprinkle 1 teaspoon Barbecue Rub inside body cavity and 1/2 teaspoon inside neck cavity of chicken.
Rub oil over skin. Sprinkle with 1 tablespoon Barbecue Rub, and rub over skin.
Pour out half of cola (about 3/4 cup), leaving remaining cola in can. Make 2 additional holes in top of can. Spoon remaining 1 1/2 teaspoons rub into cola can. Cola will start to foam.
Place chicken upright onto the cola can, fitting can into cavity. Pull legs forward to form a tripod, allowing chicken to stand upright.
Prepare a fire by piling charcoal on one side of grill, leaving other side empty. (For gas grills, light only one side.) Place a drip pan on unlit side, and place food rack on grill. Place chicken upright over drip pan. Grill, covered with grill lid, 1 hour and 15 minutes or until golden and a meat thermometer registers 180°.
Remove chicken from grill, and let stand 5 minutes; carefully remove can.
Barbecue Rub (yield: 3 Tbsp.):
1 tablespoon mild chili powder
2 teaspoons salt
2 teaspoons light brown sugar
1 teaspoon pepper
1 teaspoon ground cumin
1/2 teaspoon garlic powder
1/4 teaspoon ground red pepper