2003 Lexus LS430 Questions

I had my tires changed today and when i started driving my check vsc displayed and vsc off light turned on. Any idea what happened or any fixes.

I can use my air but i dont know how to switch it over to heat

There is a coolant leak thats coming from a hole on the top of the throttle body. There is also a round metal plug that came out of the hole. Any suggestions?

The remote controlled pivot of the outside rear view mirror still works.

The "electronic receiver" that responds to the commands from the door key buttons needs to be replaced.

The trunk is now heavy and slams shut quickly.

I had valve cover gaskets replaced what else could it be?

I changed the actuator and closed the door. Now I can't get it open.

The temperature gauge went high while my car was standing on with Ac On for a while. i checked both the fans were working. so what shall i do ?

Is the serpentine belt the same thing as the drive belt?

The car gave no indication of trouble, slow start or hard to start, before this.

is there some other part that could be bad

I keep up with oil and tires, did fuel injector cleaner 4 months ago, but haven't done a tune up in a while, what should I consider in the tune up, spark plugs, another fuel injection clean? raidiator flush? what else? trying to avoid unnecassary expense.