Wavering Idle and Dropping Voltage

Javier

I've had my 'Z' for 11 years, I'm a avionics technician in the aviation business for 37 years. For those who do not know what a avionics technician is, I work on all of the electrical and navigation system of an aircraft. Battery voltage on my 2009 "Z" never fluctuated "NOT EVEN A TWICH", in 11 years. it stayed at 14.4 volts no matter what you turned on in the car. My problem started when my battery crapped out on march 2020, a week later the alternator went out and like I have never done before went to an auto parts store and replaced with one of there's. The battery voltage and idle drop started soon after. Returned the alternator to the auto parts store got another one, no joy. Returned the battery and got another one again no joy and problem persists. Purchased a brand new alternator from Nissan $650 dollars later no joy. Replaced battery with brand new high output gel battery $450 dollars later and still no joy. so for those that think its a battery, alternator, and yes by the way I did purchase two new MAS sensor from Nissan and still nothing. Its none of the above. The battery voltage drop should be so slight when operating normal that you will never even notice it ever. There aren't enough system draw in a car to overcome a 120 amp alternator. I have contacted Nissan and they are mute about this issue. If someone comes up with a fix please advise.