Oh yeah...... there is a pretty good thread on here that outlines my experience with this shudder. Huge design issue with not only the blazer but with many other GM cars and trucks. The silverado was / is horrible and they have tried different exhaust systems, engine control units, moving the engine in its mounts with no luck. My Blazer sat at the dealership for over a month, just to have GM tell me that they test drove other Blazers and they all do it..... There is no bulletin for this on the Blazer