Random start problem (extended cranking)

I have a 2005 Tacoma 4.0L, 240K miles. The truck runs well, mpg seem normal, no codes. The problem is it will randomly crank about 10+ times before starting. 9 times out of 10 it'll crank 3-4 times and start which has been its normal. I can't figure out for the life of me why that one time it sits and cranks but it always starts.

New parts with the last 5-8 months:
Battery
Fuel pump
MAF
O2 sensors(denso)
Plugs

I'm leaning towards plugged or leaking injectors but I have none of the other symptoms of such. Maybe the Fuel Pressure Regulator? Again, no other symptoms of a bad one. I've read other threads pointing at a coolant temp sensor. It, too, seems to operate normally.

 

I would want to put a fuel pressure gauge on it and check and make sure fuel pressure holds when the engine is off.
Pressure should not drop below 21 psi for at least 5 minutes after the engine is turned off, if it does you have a bad check valve in the fuel pump, a leaking fuel pressure regulator, or a leaking injector.

 

Looks like I have my work cut out for me. Thanks

 

my '07 has about the same mileage and does the same, and has for some time. Very random. When I crank, if my truck doesn't fire right away like it usually does, I don't keep cranking. Instead, I shut off the key and start over and it has always fired quickly, as normal, on the second try. So, I haven't done anything to fix it, for now.