My 95 2wd had a weird exhaust rattle that started today. Took it into my local shop he found my heat sheild around the spark plugs was one rattle which was resolved with a pry bar. The second noise was now louder he said one of my cats was going. He suggested to replace the cats with straight pipes and because I dont have any o2 sensors on the cats this shouldn't be an issue. He said the air tube could be left disconnected where it went into the cat. Does anyone have any thoughts on this issue?