[Kevin Price]

Check how you have your wiring to the starter relay (in the engine bay).

You should have a larger cable that runs directly to the starter. You shouls have a separate wire that runs to the starter solenoid, directly above the starter. The smaller wire MUST BE ON THE OPPOSITE POST AS THE BATTERY CABLE/CABLE TO STARTER.

If they are both on the same post the starter will not disengage correctly, much like what you are describing. Check that first, I bet that is your problem. Good luck!