The last time i drove my car i happened to hear a noise. my friend wanted to hear the pipes i have so i revved the engine. All of a sudden i heard a slight ticking or banging sound, sorta in the middle of the two. It rarely does it, the car runs fine. it didn't do it in gear i believe. the one time it did it out of gear and it continued the car started to stall then caught itself. any ideas?