Set up the grill for direct cooking over medium heat and oil the grates.
Slice the pound cake into 3/4-inch thick slices with a serrated knife.
Using car-shaped cookie cutters, cut out car shapes from the slices of cake. Brush with butter and place on the grill. Cook until nice grill marks appear, about 3 minutes.
Meanwhile, in a medium bowl, combine the whipped topping, cream cheese, and coconut extract.
Frost the car shaped cakes with a small amount of the coconut frosting.
To decorate the cars: Use ribbon candy as racing stripes, rock candy as windows, and mini chocolate sandwich cookies as wheels.