93 Sidekick 16v 1.6 5 speed. Problem starting, sometimes it will other times it won't. Turns over, battery voltage good. Good spark and good fuel pressure (45 psi cranking). Motor has been rebuild compassion is 180+. Good known computer Crank shaft Key is good. Runs excellent when it is running. Holds 35 psi fuel pressure while running. The next time I try to start it, it will not start. Still have spark and gas. Could there be something causing it not to inject? Didn't check with a noid light yet. At time it will start to a low idle and go to a stall

Having the same problem with my Tahoe, and fuel pressure is good,I would suspect electrical.
Coil, wiring connections,grounds to name a few. My problem was a distributor cap screw working
loose at times loosing rotor connection. PAIN to find! Once it started in the morning, it ran and
started perfectly all day. You just never knew when it was not going to start! 
Check you iac valve for stoppage also. Those 16 valve egr tubes seem to soot up a lot
also. I suspect poor fuel quality is part of the culprit in those cases.
I would add a little starting fluid in the intake to see the reaction when it doesn't
start first. Not a lot. Just enough to see if you get a cylinder or two to hit.
Press the gas pedal a little while cranking and see if there's a difference.
Good Luck!!

You've verified spark, and fuel pressure, I'd say next step is to determine if you're getting fuel into the cylinders - either pull a plug and see if it's wet or use a noid light.