Starts up but immediately dies. Almost like VATS is shutting it off. only idles for a second at the most. No matter if I hold the throttle or not. Any suggestions?

I've swapped out the PCM with another one, I was told one was tuned out. The other PCM had no spark, so I put back the original one that I was using.

Checked codes, getting U0107 Pending and 2 other O2 sensor codes (the Precat 02 on the driver's side is the wrong connector so it's unplugged)

I know that there is no fitting on the intake for the fuel pressure regulator so I know it's getting full pressure from the pump, but I don't think it would be enough to completely choke out the engine that much.

Any ideas?

-Matt