Intermittent 2010 M3 won't start
 

I have manual trans. Sometimes I turn the key nothing happens (silent). If I turn on the ignition; put the car in 5th gear; give it a hard push on the trunk lid; then the car starts instantly every time. Pushing must turn the crankshaft a little even though the car doesn't move any noticeable amount. This started about a month, and it keeps happening more & more often.