Grease and heat grill to medium-high heat. Grill pork tenderloins evenly, using tongs to turn every 4 minutes and basting regularly with peach sauce. Once exterior is nicely charred and an instant thermometer reads 145°F at the thickest center portion of pork, it’s done (approx 12-14 min, depending on thickness of pork.) Immediately remove from heat, transfer to cutting board, and let rest 10 minutes (do not slice yet.)