Mike1985

Hey all, when I accelerate hard on my 85 you can hear a very loud rattle which sounds like it's coming from my exhaust. Just wanted to know if anyone else experiences this as well..

John A. Marker

Check your cat to begin with. See if it rattles if you shake it or slap it with your hand.

Then check for clearance on all the pipes and mufflers between the body. Check the heat shield above the cat.

Check the mufflers to see if they are perhaps rusted out inside. Shake or slap the mufflers.

s carter

a lot of the things to check were mentioned above, the only things I will add is check front weld on rear Y pipe heat shield and see if it cracked, and pre Puff converter (the little converters on each side) cars were prone to inner wall separation of the Exhaust pipes. to diagnose raise up car and run it have someone raise the idle to make rattle. take a pair of large channel locks and give lite squeeze in various places on front Y pipe, the rattle will diminish or go away. if rattle changes take a ballpeen hammer and put a small dimple in place were you squeezed.

DinoBob

My guess is cat heat shield.