I am driving a 2000 Ford Explorer with 140k miles on it. Although the car runs well, it feels like it is on the verge of a breakdown that I'd like to stay in front of if possible. When I start the car, it puts a little slowly, but eventually starts. In the couple hundred times I have started it, it has only died post start (ran on second) once. When I am stopped at a light, the car shakes a little bit. Lastly, I notice the smell which is basically smells like something is hot. I have no lights on and oil/temp all seem to be fine. I had it in a shop a couple months ago and they had assured me it should be running fine, but I cannot seem to stop anticipating a break down. Any ideas?
Also not sure if possibly related, but the electronic keys I have with the car can barely unlock it.