OK, so it's an idle vibration. Has nothing to do with driving. And as things lower the engines idle, the vibration gets more pronounced. Idle in neutral, it's fine. Put it in drive (or reverse), and the idle drops and there is vibration. Turn on the lights, and it vibrates more.

This may well be normal. The engine is not perfectly isolated from you, and as things pull it down, it will get a little rougher. More so on an engine with years of service. You may be reacting to a non-problem.

But, there are some basic things you can check and deal with.

1. Clean the throttle body. A whole lot of idle roughness happens here when it's dirty. A few dollars on a spray can of throttle body cleaner and some paper towels.

2. Check the base idle. I don't remember the steps off the top of my head, but you jumper and make sure the base idle speed is correct. This makes sure the air motor that adjusts idle for different loads can do its job correctly.

3. Check for obvious dumb loose things. From that screwdriver left beside the valve cover to a broken hood support clip. Things that would rattle and vibrate.

4. Check for lose and broken vacuum lines and such. Fix what you find, if you find anything. Don't forget to check the switching valves for the front axle!

5. Check the battery and its connections. If they are bad the alternator has to work extra hard, and this can pull the engine down.