Momentary power failure on dash, stereo, and now engine
 

Hey All,

I have been experiencing a problem I’m hoping one of you can help diagnose. It was a minor issue before but manifested in much more serious symptoms this morning.


What happens?
- All lights on dash will go out momentarily, the tach and speedo will fall to 0, the entertainment center will restart, and any connected accessories will flicker or restart (air ride controller and radar detector).
- When this first occurred, the stereo stayed on, continuing to play music, but the screen went black and restarted.
- Upon power back to the dash, all warning lights would momentarily illuminate as if one were cranking the ignition, and then everything would be back to normal.
- This all happened in the span of a few moments.


Car:
2012 G37s Sedan 6MT w/ Bose, ~85k miles
Relevant modifications: two amps, air lift performance air ride system w/ management + two compressors, optima yellow top battery, grounding kit.
- Airlift harness and power for the amps run from the positive lead on the battery (where they are fused) to the rear of the vehicle through a slit cut in the stock harness grommet and then sealed with silicone. There is no sign of leaking on the passenger side.
- Airlift harness is grounded at the battery, amps are grounded in the
trunk


History:
Recently, I did find water in the DS footwell floor of the car after noticing a wet spot by my feet. I removed the entire interior, pulled the carpet, and replaced the interior to run carpet-less until I solve the issue. There is some surface rust in the footwell so it’s been exposed to moisture for some time, and I believe I have narrowed the issue down to the dreaded clogged / failed sunroof drain tube on drivers side which I will be fixing this week.

Additionally, the car has a history of throttle response / rev hang / idle issues, which have been occurring since I’ve owned the car, which was stock when I bought it at 35k miles.


Worsening symptoms…
This morning on one of the times when it occurred, the engine was sputtering as well as though it were losing power, in addition to the above systems. Also, this time, the entertainment system audio did cut out (not just the display). So the issue is not limited locally to one aspect of functionality, which leads me to believe this is a broader power issue or an ECU issue.


How frequently?
This first happened about three weeks ago, but occurred again this morning, though this morning it was worse and happened multiple times (three, I believe).


Common factors?
I believe this has only happened in the rain. I think it only happens under acceleration, but I am less sure about this.


Any input would be greatly appreciated!

Check fuses