Had this problem with a Maxima a few weeks ago.  Engine
seemed to have everything it needed to run but would only
attempt to start occasionally.  An old Nissan tech suggested
it might be flooded.  WTH.  With nothing to lose, we simply
held the accelerator on the floor to put the ECM in clear
mode, hit the starter and cranked it continuously for about
10 seconds.  Started with a cloud of black smoke and ran
beautifully with no further problems.  BTW, fuel filters
almost never cause sudden loss of power or no start unless
they get a large slug of water.  Fuel filters almost always
first show some signs of impending failure like power loss,
surging, lean misfire or other indications before complete
shutdown.

Lugnut