so my 91 formula with duel y-pipe with no cats will not stop rattling. it rattle when i first start up the car for about a few min. then when im driving on the highway it rattle so bad people passing me looks at my car like its about to breakdown. the car is in very good shape and im seeking advice on what to do about my exhaust problem? i don't want to replace it. so what am i left to do? its rattle right under the passanger side of the car. im almost 100% sure its the y-pipe.

 

You might check the heat shield.

JamesC

 

My 1st thought about header wrap... rust. Some guys like it and swear by it, I dont like it.
Check your heat shields, if the car has a bunch of miles you may have broken converter guts.

 

Can you hear it at idle?
If so put the car on ramps. My suggestion would be to have someone in the car foot on the brakes. You lay under it, then start it. You will hear the noise. Where you hear it, put your hand on the exhaust. If it stops that's where your problem is.
Could be a loose heat sheild, loose bolts, etc...
Putting a wrap on it may muffle it, but will do absolutely nothing to fix it.

 

well today i went out took the heat shield off the car a still here the rattleing. Its not my cat because i have none. I just think it my damn y-pipe. its as old as the car so seeing as its rusty and old im guessing its just loose or something. the noise is louder on the passanger side of the car then its is on the driver side.

 

ok cats are gone. is the air pipe still there? or the mounting welds broke? there is also sometimes a lil bracket welded between the 2 pipes from the factory. the weld can brake and cause the noise

 

very good point. but i removed the air pipe. i will check were i cut the pipe. maybe were i cut its hitting the metal exhaust. Good thinking sur.