Thanks for your reply!
I will try to describe the vibration, During idle and in any gear, you can feel the seats and steering wheel vibrate. When driving it seens normal the vibration only comes on when the car is idling.
I went to my mechanic and he said that my exhuast is faulty not the muffler but the front or middle part of the exhuast. I have also changed my engine oil from 15W-50 (Shell Helix Ultra) to 0W-40 (Mobil 1) and my spark plugs to irdium ones. Could these be the cause?
Thanks once again!