[SoCal LS-L]

Unfortunately cranks-no start can be a pain to diag.

One shortcut is to spray some starting fluid thru one of your vacuum ports, and immediately try cranking over. If it wants to start then, you verified spark, and if it starts up then dies, you have properly timed spark... and can focus on the fuel system as a cause.

If it has no effect at all, then I would look at the ignition system or air/temp metering.

Try the starting fluid thing and also check for any codes, then report back and we can take the next step.