Whisk together olive oil, vinegar, sun-dried tomatoes, garlic, 1/4 teaspoon of the salt and 1/8 teaspoon of the black pepper.
Place pork and 2 tablespoons of the oil and vinegar mixture in a resealable plastic bag. Shake to coat pork, and refrigerate 2 to 4 hours.
Place potatoes in a medium saucepan and cover with water. Bring to boiling and simmer 10 minutes; drain.
Heat a gas grill to medium-high or the coals in a charcoal grill to medium-hot. Thread pork onto 2 skewers, potatoes onto 2 skewers and vegetables onto separate skewers. Brush generously with oil and vinegar mixture.
Lightly coat grill rack with oil or nonstick cooking spray. Grill vegetables 5 to 6 minutes and potatoes about 4 minutes, turning a few times and brushing with oil and vinegar mixture. Grill pork 3 to 4 minutes per side or until internal temperature reaches 145 degrees. Brush with remaining oil and vinegar mixture. Sprinkle remaining 1/2 teaspoon salt and 1/8 teaspoon pepper over skewers before serving.