my muffler was vibrating in idle when it had a hole in it when it was ****ed up. it was really load too, so i ordered a new one.

i put on the new muffler, the sound is gone completly, but it still vibrates and sorta sputters when it is idling. it idles at about 400-500 RPM

i can see the whole muffler vibrate and the fumes don't flow out smooth.

what could this be, i really need help.

thank you very much

 

clogged cat? crushed pipe somewhere? idk.

 

there is no curshed pipe anywhere, but the cat might be clogged how would i check and or fix that?