I am wondering if the exhaust should have this deep rumbling sound or should it be a lighter like burbling sound. The exhaust system has been changed 2 months ago and when it was installed, the sound was alright. Now when I put my palm against the open exhaust, the pressure is quite great as compared to my Camry which only has a very muted note and quite a gentle outlet pressure. Could I have some valves stuck open and problems with the timing chain and so forth. I know very little of engine theory. Or could the exhaust have gone so fast. Its OEM back and middle, but the Cat is after market(not that it would make any difference). In the car, I can feel and hear this rumbling sound from the exhaust. I am sure it wasn't designed to do this as it is annoying. Could this be due to the fuel I am using? Its 92 octane regular unleaded here and I use it being cheaper. Will the noise go if I change to 96 octane premium? Funny thing is that I was trying a for sale C180 Esprit 2 days ago and it just didn't have the power or guts of my Elegance. The engine is the same, but is the tuning different? I had my foot on the floor and it wouldn't go many times while going at 60kmh. Anyway it has been sold, sorry to the new owner!