That sounds like a horrible electronics glitch of some sort. If that sound came out of my mustang, I would take it to the dealer immediately.
That is most certainly NOT was I was referring to as a low battery warning
Thats what they are supposed to do at idle.
Now like I said earlier, park the car and have someone give it throttle while you watch the valves. They will open and close with RPM in Normal and Sport modes
I can confirm these hashmarks I drew indicate 140⁰ on the left and 200⁰ on the top. Assuming the gauge is linear, that means Orange should be 260⁰ and Red is probably 275⁰ or so.
I noticed under the auxiliary gauges that the oil temp has Blue, Orange, and Red thresholds that correspond to temperatures. But there are no actual value increments that say what those temps are.
I know you can see the actual temp number in the digital gauge cluster. And obviously anything in...