Car will not rev. Idles very rough swinging high and low. Where to start?

What is your question?

The car has been idling rough at idle for some time now. Once going it acts fine, but the fuel trim would stay around -40%. Yesterday the car wouldn't even rev up, I thought it would be much easier to pinpoint the issue. I reset the codes and immediately got these codes. The idle would swing high and low as the high pressure fuel line would swing from 200psi to 2500psi over and over. This is the chicken or egg question for me. I don't understand where the problem can originate, or if it's a closed loop type control and multiple things could be the issue. Hoping for best advice for order of parts replacements. I am using HP Tuners and have a log file saved of the rough idle. Here are the codes. P0641 - Sensor Reference Voltage A Circuit/Open P069E - Fuel Pump Control Module Requested MIL Illumination P018D - Fuel Pressure Sensor B Circuit High P0641 - Sensor Reference Voltate A Circuit/Open P06A6 - Sensor Reference Voltage A Circuit Range/Performance Thank you for any help!

What makes this problem better or worse?

Nothing in particular

How long has your 2010 Cadillac SRX had this problem?

small problem for many months. Big problem for a few days