I have a 94 Ford Explorer 4x4. It has a lot of miles on and I know I should expect some trouble. My Check Engine light came on last week and I tried to diagnose the problem myself. I bought the little computer reader and plugged it in. Only one problem, I was more confused after I plugged it in than before I started. I called my mechanic yesterday to ask if I could drop it by his shop so he could look at it today. I went over with my wife following in her car about 5pm yesterday afternoon. We...