My car has been having a hard time starting, making an awful sound when I do so, also when I’m idling at a the lights. It sounds as if something close to under my seat is rattling. I’m thinking it could be the exhaust. A couple months ago I hit a pot hole, the next day I started hearing the noise. Had a couple people look at it saying it was just a piece of metal that broke off that held the exhaust in place, but that it was still on nice and tight. Thinking it could be the exhaust heat shield rattling. Also has been having a hard time getting up hills and getting to up to speed somewhat fast. I think that’s due to the spark plugs needing to be changed. Also has been sounding more like a truck while driving. Any ideas of what else could be happening?