Backed into a parking spot today with my tailpipe facing a concrete wall only to hear a loud metallic crackle and popping sound. It was so loud that I pulled forward a few feet to see if the sound diminished as I moved away from the wall. It didn't, so I backed in and was about to shut off the engine when a person in a Volvo wagon parked next to me said "Your Prius is making a horrible loud noise, what's wrong with it?" "I thought the Prius was supposed to be a quiet car." Then she backed out and drove off, and the noise left with her. My car must have provided enough echo to amplify the struggling engine in her 90's Volvo. What a relief, although I can't imagine such a noise being generated from the back of a PiP, even with the ICE running.
