What a jackass that owned the car before me. I finally have it running nice and all of a sudden the car backfires a couple of times and stalls. After finnally getting it started again it running rough and loader. I also notice a sort of ring at the muffler, I go and check and the PO did a great job repairing a hole in the muffler. He riveted a piece of licence plate over the hole, copered with muffler sealant and painted the muffler. Would this hole make the car run rough and keep stalling?

not too likely, sounds like a fuel or ignition issue to me, most a bad muffler repair would do is either plug the muffler causing it to just die immediately or not seal properly making everything louder

That's a pretty ghetto repair.