I drive HHR'06 LT.
Past few weeks, it starts to make popping noise, link "dunk" sound. It sounds like my car is about to break down and entire car vibrates. I can't figure out what is causing this noise, it's certain that it makes noise under the hood.
It really irritates me and hurts me ears now, when I drive long distance.
What's happening to my car?

 

I don't know, but I'd get it to a good mechanic soon! Vibrating = not good.