I would appreciate any thoughts on this one! My car developed a strange sound and/or vibration that seems to be related to the engine and/or exhaust. The car is the same at low RPMs as it always was, but at high RPMs (6,500+), it is louder and I feel a somewhat frantic vibration. If I then engine brake (coast) down from high RPMs, I get little stutters in the exhaust note, whereas I used to get a gradual lowering of exhaust pitch as the RPMs came down.

Has anyone experienced anything similar?