I put on my summer rims yesterday and had them balanced. I can feel slight steering vibration particuarly at highway speeds so I assumed they screwed up my balance or didn't remount them right. But today I noticed I can feel the vibration even when in park. So I opened up my hood and you can definiely feel the engine vibrating. I know an engine has moving parts and wont be completely but its clearly vibrating. So I touched the wheels and they're also vibrating which would explain the steering wheel. The exhaust is also vibrating all the way at the back of the car. I've also noticed that when accelerating lightly up or down hill I can hear a weird noise coming from the back of the car. A person in the back seat particularly said he thought it was a wheel well which is right by the exhaust. I'm about to bring to my mechanic cause I'm assuming something's up with the exhaust but I wanted to see if anyone else has had a similar problem or knows what could be wrong.

 

Just went out and played with it some more. Turns out the vibration is worse at lower rpms. I sat in park and rev up to 3000 and the vibration was pretty much completely gone. Then as it dropped I could feel it get worse and worse. Also its been having a little trouble starting up lately. Particularly if its cold or its been left a few days. It will start rev up to its usual rpm and then just drop to 0 and die. Then when I start it up again and give it some gas it runs.