The whole inside of my 1995 NA 850 buzzes with the engine at idle, it is much worse when in gear than in neutral. There are lots of notes in the archives that point to motor mounts but I don't see how to diagnose which mount is bad. I looked at the front right mount (behind plastic panel behind front right wheel), the vertical pin thing is not sitting at the bottom of it's slot. I don't know if that means it is definitely good or just that it is not definitely bad.

Someone suggested prying up next to each mount to see if the buzz goes away, I'm not sure I see how to do that.

The car has 128,000 miles on the clock. I bought it at 91K but have copies of all service records. No mention of replaced motor mounts. I replaced the top mount a few years ago.

So how can I tell which mount(s) is (are) bad?

Terry

A couple suggestions:
1) If you jack the car on stands, and the sound is gone, it's something else. On stands and if the sound is there, you go underneath and with a prybar, place it near the mounts and pull up / down to see if the sound goes away.
2) Does this happen more in forward or reverse? With someone else in the car shifting from forward to reverse, watch the engine movement, if any. This mostly shows the upper mount is going, but you may see something underneath.
3) Can you get ahold of a stethescope? With the engine running and car jacked, crawl around underneath by the mounts and listen.

Hope this helps