Combine first 5 ingredients in a small saucepan; stir in 1 tablespoon vinegar. Bring to a boil over medium-high heat. Cook until reduced to 1/4 cup (about 3 minutes). Reserve 2 tablespoons agave mixture; set aside. Keep remaining 2 tablespoons mixture warm in pan.
Heat a large ovenproof nonstick skillet over medium-high heat. Coat pan with cooking spray.
Add pork to pan; cook 5 minutes, browning on all sides.
Bake at 350 for 10 minutes.
Brush pork with 2 tablespoons reserved agave mixture.
Bake an additional 5 minutes or until a thermometer registers 155 (slightly pink).
Let stand 5 minutes.
Add remaining 1 1/2 teaspoons vinegar, 1 teaspoon water, and red pepper to remaining 2 tablespoons agave mixture in saucepan.