What can cause my 2003 Nissan Altima to not cranck sometimes and sometimes it will if the engina is running a while and I cut it off it will not crank back up what could be the problem

When a starter will not crank the engine over, there are normally four possibilities. 1. A poor connection at one or both battery terminals. 2. A starter solenoid needing replacement. 3. A faulty ignition switch. 4. Internal problems in the starter, which may include worn brushes or a shorted armature or field coils. If you hear the starter spinning, but not cranking the engine, then either the solenoid is not engaging the pinion gear with the engine's flywheel or the flywheel has one or more gear teeth missing as a result of damage. If you don't hear the starter spin when you turn the key then possibilities 1, 2, or 3 should be checked out.

Most likely, your starter is failing. Change it before it dies completely. Less likely, you may have a safety interlock (neutral selector switch or clutch switch) that is failing.