2014 Silverado goes lean just driving slow

[Lakegoat]

5.3 bored and stroked to 408. Ported heads, forged internals. ZL1 fuel pump, FIC LT4 30 over injectors, Magnuson SC, 240/250 cam with +33 percent fuel pump lobe. 6L80 trans.
Starts and idles fine. Idle timing is all over the place
The short log is just sitting still and giving it a little gas. I'm afraid to drive it like this.
Fuel pressure is NOT steady. Fuel pressure Looks like the idle timing log.
Came back from a shop that could not finish the job.
Anybody know why the fuel pressure is so erratic. I am not familiar with the E92