Looking for a little push in right direction. I have a 2016 pro-charged Z06 with twin nozzle Alky Control system and DSX AUX low side and E sensor. Car was moved from sea level to 4800ft and customer wanted a checkup to make sure everything was good. Went for cruise and noticed the low side does something I have not seen that wasn't a AUX low side check valve or controller issue. The low side pressure pulses like nothing I have seen. Put mechanical gauge back by the tie in point for AUX low side and pressure pulsed from 60psi to 70psi while the data log showed pulsing from 40psi to over 100psi at times. I know the mechanical gauge isn't necessarily going to show these pulses in good detail but was able to give a picture of what was going on. The mechanical and ECM pressures were within 2-3psi with engine off. Added known good check valve to isolate the AUX low side and the system behaved the same. Worked with DSX to verify low side control and pump are doing what they should, and they are. Dave was also nice enough to verify settings in tune were good and they are. I have to believe it is not a tune problem as the low side setting have only been changed for proper low side control. AUX pump will prime and set system to 95psi, with engine off. The factory fuel system will set system to 65psi. The system does hold pressure for over an hour, slowly dropping and never getting below 45psi. Only when heat soaked will the system pressure bleed off to 0 which then creates a hard hot start with an upset high side and engine for a couple of seconds. The hot start issue will be addressed after the low side gets figured out as one could be leading to the cause of the other. Replaced the low side factory sensor with new GM part and similar results, the high spikes are less pronounced but still there. Meth system activates and goes green like it should, the low side comes on when commanded and the fuel pressure still fluctuates wildly even during a WOT pull. HPFP pressure never drops off, so the fuel has to be there, just cant trust the low side pressure sensor.
Have I gone down a rabbit hole for no reason? Like is this an OS issue or is this signs the low side pump/regulator maybe even the HPFP is dying?
Attached is the log of a idle and cruise.