I have a 91 olds royal 88. In the summer it runs terrific and no
problems..in the winter ( i live on the coast so lots of rain)it does all
of this... When you step on the brake, with the car in park, it dies. When
you put it in gear, it dies. When you slow down to stop and step on the
brake, it dies. Its done this for 2 winters now. Lately its also been
doing this...you will go down to start it and you get nothing. As if the
battery is dead. But then  a few hours later you can go down and it will
start right up, a bit rough, but it starts. Also, sometimes when you step
on the brake the headlights flicker or dim.
Any ideas?? In the past 3 years the battery, starter and alternator have
been replaced.