2008 Infiniti g37. I turned my car on . many dash lights turned on (Slip, vdc off, AFS, etc..) headlights begin to flicker and then stay on (headlight switch is in the OFF position) I noticed radiator fan would turn on and off along with the headlight. and now my car wont shut off. after pushing the "Push-Start" button several times. also RPM and temperature gauges are unresponsive and also flicker up and down randomly. I managed to shut the engine off by pulling the MAF sensors. but it wont get off ACC mode.

 

Water intrusion of the BCM is my first thought. That is a common point for most of the things you listed that are acting up. Maybe the sunroof drain failed and water is leaking on the BCM? Or, was it in a flood recently or salvaged from a flood? (just reaching for ideas, but would really look at the BCM to see what is going on)

 

that sucks and is crazy scary to not be able to turn off an engine. my g is my first pts car. in an emergency situation to turn engine off rapidly press pts 3 times or hold in for more than 2 sec.

i agree with above sounds like water/electrical

good luck