Starter on 1990 Pontiac Bonneville

Its actually a 1986 Pontiac Bonneville - When engaging the starter it sometimes sounds like your are grinding the gears. Sometimes it does it when you first try and other times it does it at the same time it actually starts and it is not from holding the key engaged too long. The starter has been replaced twice in the past 2 and a half years.

there may be teeth missing on the flywheel. have a shop check the flywheel for damage.