2003 Nissan Altima 107,000 miles Service engine soon light came on. Went to Auto Zone and got: P0302 Misfire in cylinder #2 Probable causes: 1- Ignition system fault-spark plug(s), ignition wires, coil 2. Vacuum leak 3. Injector fault 4. High or low fuel pressure So...I decided to change my spark plugs (which I haven't done yet though) and pour in some injector fluid. Do I or should I change the coils? Are the coils the same as ignition wires? What's a vacuum leak? I've recently had an oil/filter change at one of those oil/filter places and they check for leaks...I had none. Does that have anything to do with the vacuum leak? Meaning...I shouldn't worry about it? What's # 3 and 4? What are ways to know if I have to worry about these as well? And... what are the solutions?

I have a 1994 Toyota corolla, the 2 bottom rear brake lights work fine but the high mounted brake light (collision light) doesn't work. I have replaced the bulbs but still won't work. Any ideas? Thanks.