while i was driving yesterday...i heard a metal grinding noise when i was at 70 mph. this only happens at 70-75mph. so weird.
when i accl. from 70 this noise seems to appear and also when i break from about 75 this noise hits again. so weird...

any of you Z owners have this problem???

 

I once had a similar (not metal grinding) issue in my prelude... It turned out to be a hunk of ice stuck to the inside of a couple wheels. from 80-90 I would feel a wouble.

I don't know what inside the engine/drivetrain could cause a balance issue though