please help with codes on my sisters Z28 have EFI live log
 

I am doing some tuning on my sisters 98 z28 and every time I floor it hard it with throw an ses light and have these codes. P0131, P0151, P0137, P0157. It also will stay in closed loop when this happens. I even flashed it back to stock and logged it and it done the exact same thing. Don't mind the knock retard because I fixed that. Anyway it sets the codes and light even with the stock tune. Any idea what this could be? The car is stock other than an slp lid and a flowmaster. Below is a log

Low fuel pressure at WOT.

would that be the regulator or the pump?

Low fuel pressure is usually the pump. Check it with a gauge. It can also be OK at idle but not at WOT. If you can't check it on a dyno, then another way is to tape the FP gauge to the windshield and go for a drive. If the WOT AFR in the log is just the commanded, then the narrow band O2s are not reflecting it.