I've got a wierd problem with my 03 maxima. Once in a while (very rare), when i turn in the key, all i hear is a humming noise, no crank click nothing....
battery is fine n all... and then after abt 10-15 mins after a few tries, the car starts up with a struggle)...

never experienced it with other cars... but whats the issue? starter? ignition switch?

could it be immobiliser system?

 

Cant be immobilizer because if immobilizer is active, the car should crank but never start.

 

Just run down to a local store and have them do a starter test could have have a bad spot on the armature in the starte and it only lands there every so often causing intermitint no starts

 

Another possibility is the ignition switch. The hum sound you refer to could be the fuel pump.