OK, this morning it finally happened - the Maxima couldn't get me to
work.  (Had to take my twin turbo RX-7, hehe :)  Before now it would take
about 5-6s of cranking before the engine would start, but it always started.
Usually when the engine was cold.  When warm, it usually started as normal
with only 2s of cranking.

   Cranked the starter for a good 10s about 5 times and the engine never
started.  CEL came on, and the codes were 0101 and 0304 (Knock Sensor and
Camshaft Position Sensor).  I've checked the CmPS system per the Factory
Service Manual and it's good.  I did a quick check of the Knock Sensor, but
the manual says it won't affect starting.  I also tried letting the ignition
'On' for a while before cranking but it didn't help.  I've been getting
those codes after a couple of hard start episodes.  Also, this morning I
noticed a fuel smell very briefly for the first time.

   Nirav suggested the Engine Coolant Temperature Sensor.  So I changed
that this morning and it didn't fix things.  I haven't yet done the
continuity check on the ECTS wiring due to time, but I doubt that's a
problem.

   Maybe these are basic questions but:
- Does the FSM have a starting troubleshooting flowchart?  So far I haven't
found one - the section on 'starting' is just a bunch of electrical diagrams
and how to pull the starter assembly.  I skipped it since the starter sounds
like it's been working fine and it's not very old.
- What's the best way to verify spark and fuel pressure?  Should I be
checking the injectors next?

   Thanks for the help so far, and thanks for anyone who contributes
further.

   Dave