It just so happens that I too have some similar issues with my 740 N/A with B230F. I just had the harmonic balancer replaced (it was separated). That was good. Also, the crank sprocket gear? (you know the one I'm talking about? Behind the harmonic balancer?) Anyway, the key was sheared off. Wasn't sure what caused that. After all that was replaced, checked the timing and it was apparently 15 degrees too far advanced!!! At idle, made a huge difference after adjusted. What changes did I notice? Well...the brick idles a hell of alot better now (ie: not as noisy). However, the engine noise/vibration that was noticeable at 2500 rpms has now moved up the rpm curve to about 2900rpms. It seems very noticeable at that point and higher. It is the same thing that the others are experiencing but I also FEEL it as well. Could this be from exhaust cracks around the header area? If so, wouldn't I get backfires or hear it when not at such a high rpm? The current exhaust from the catalytic on back, is 1.5 years old. I've spent a bit 'o change on this issue and it is still there! I guess the good news is now I have to drive the car to 72mph to make it happen. I guess I could keep it below that speed, but what fun is that? Would bad manifold to block gaskets do this? Again, I keep thinking if it were the exhaust, wouldn't I get some indication (like popping when decelerating)?

I need your mighty wisdom Steve,

Thanks,