lysshaze

Hello, all. Having quite a few issues with my C300 and wanted to see if anyone had any ideas. All was typical the until about 2 days ago I noticed a strange noise coming from the front of the vehicle. I don’t know that I’d necessarily consider it “rattling” but it was a hum/buzz of some sort accompanied by a high pitched rattle. It seems to mostly occur when I am decelerating, and is most intense when I drop down to about 800 RPM while coasting. It seems like it’s downshifting when I let off the gas because it’s decelerating at a much faster pace than normal. My car also started pulling significantly to the left but I’m fairly certain that is because my tire is shot and is not correlated. Replacing the front left tire to see if that fixes part of the issue. Curious if it could be a bad cat or some other issue. Sorry for so much information and so many issues at once but just curious if anyone has any knowledge on what is/is not correlated. Thanks!

Phoenix222

This doesn't help you much but I can tell you that I have what sounds like a very similar issue. I get the same deceleration issue mainly when going down a hill. I have a hum coming from the front end usually when going over 40mph though I did get new tired and it helped but I can still here the hum or some sort of constant vibration.