When i turn my engine off on my 2000 TL i feel a vibration from under the car and noise. I think it may be my catylic converter because my car used to misfire and stall at warm startup and the catylic converter would shake a lot and you could hear it. So i got rid of that misfire problem but now at turn off i feel a vibration and noise similer to the big shakes, but on a way smaller scale. Could my cat converter be damaged? I have no CEL anymore! (Used to get it amd it wss a misfire) changed a coil.

 

The best way i could describe the noise at turning off is like a rattle and its coming from the middle/front!