So I noticed the dummy oil gauge did a little wiggle when I put car in reverse and then it stalled like it turned the key off when I let it sit in park for a bit. It bounces off a lower than normal rev limit in park the a loud pop in the intake and it’s normal as I can rev it much higher like...

I just recently bought a 2007 ford crown vic p71, and when my key is completely off the car keeps powered to all the accessories like radio, wipers, and windows... What could be my problem?