Cranks but won't start

An incandescent test light is not a good way to check for pulse. First off, your looking for a ground signal, not a power signals and the but can damage the quad drivers in the PCM. Once you get a little better feel for exactly what is dropping out whether it be power supply or ground pulse and for how long, you can pursue a more specific path. We have probably gone as far as we can in this venue because it's going to take some in depth diagnostics.

It might be time to start taking a closer look at the cam sensor and related circuits.