As previously posted, I went to a Volvo mechanic instead of Midas and the mechanic put a Bosal front muffler on my car. After one day, I guess the clamps came a loose and it started making a loud scraping noise. I took my car back to the mechanic and he tightened the clamps. I test drove the car upon completion with the mechanic in the car and the car was fine. After driving around all day, later on I noticed when my car is idol, it makes a slight thump thump thump noice and you can feel the floor of the car shaking. Is this normal for a 86 Wagon, or is this a problem with the muffler. I do remember before I had the new muffler, I didn't have this vibration. My car shakes like an old bucket now. Before, I was amazed at how silent the car was when idol. It seems like the old muffler was better than this "Bosal". Does anyone know what this might be? I am going back to the mechanic in the morning.