Did you do a cut the wire job or use a wiring harness.

I always recommend a harness sit down at work bench and go over the instructions for radio and the harness. What is the brand of aftermarket head unit

Road brine, did it snow, or is it close to freezing where you are.

You need to get the car on a lift with a mechanic to check it. The internet is your friend, but it can’t fix the car.

Burning oil , are you sure it’s not leaking oil?

What are the dashboard lights that won’t turn off.

I recommend disconnecting the battery for 30 minutes to see if the light on the dashboard goes off.

Had the car been in an accident or anything in cigarette lighter