My cammed 98 z28 hestitates for a couples seconds off idle to about 1200rpm and once it goes past 1200 it runs fine. For some reason I am hoping that it might be tuning issues, but lately I have found metal flakes which stick to a magnet from the dipstick. I think that one of the bearings is going in the engine, but wouldn't I experience this throughout the entire rev band not just idle to about 1200rpm? Any ideas? Thanks.

-Phil