Porsche is asking owners of its 911 GT3 models to stop driving them because they can develop engine problems and catch fire. The German sports car maker says it will pick up the cars and take them to a dealership for inspection. The problem affects 785 GT3 cars from the 2014 model year, including 408 in the U.S. Porsche says engines were damaged on two cars in Europe, and both caught fire. The company says there were no crashes or injuries. Spokesman Nick Twork says oil caught fire in both cars.