my 3rd cat on my 95 4.6 cougar sounds like a tuna can lid on sand paper when i stomp on the gas. i was wondering how much it would cost to fix but then wondered, do i NEED the third cat to pass emissions? no engines bigger than factory option pass here for those who were wondering.
imo i would put the third cat back on just in case ya know.
If you don't drive up on the lawn or grass or anything like that you can remove the heat shield around it. That's most likely your noise. The tack welds on them tend to break loose causing the rattle noise. Quite common problem on various makes of cars.
k ill check that next weekend.