2006 G35x 122K Car died on the hi-way, all lights blinking, slowed to <20mph and could not rev above 2400rpm.
Put on hazards and after 15 minutes battery dead. Cannot even open trunk.
Towed it home, battery around 10VDC. Checked connections, and cleaned. Charged battery for 30 minutes and it reads 12.7vdc. I have a battery load tester and the battery tests fine. Started car, checked charging voltage 12.0 11.6, 10.5 then the car shut down.
Charged over night,checked battery in the morning at 12.7vdc, started and alternator charging voltage 14.5vdc. All seemed well.
Bought new Alternator anyway, decided before tackling this to check once more, battery at 12.6vdc, then started car and charging at 12.0vdc. Shut off car battery back to 12.4vdc.
Let sit a few hours, same result, battery at 12.6, but once started alternator sourcing it down to 12.0.
I am going with bad regulator in the alternator. HOWEVER searching the forums I see possible ECM issues.
What is everyone's thought? Bad Alternator, Bad Battery, Bad ECM? Fuses? I cannot see how it is a fuse with it working intermittently. A fuse is a go/no-go control.