I have a 1998 Lexus SC300 and when I go to brake sometimes the car will not want to stop.

I have a 1998 SC300 and when I try to stop sometimes it doesn't want to stop.
If I pull up on the parking brake it will finally stop.  I took it to the place that has
been doing my brakes for 25 years and they checked and said my brakes were
fine but the master cylinder was bad so they replaced it along with the brake
lines.  But it happened again after it was replaced. When it happened the last
time I shifted it into neutral and the engine revved when I did that. But I was
told that it would do that and take a few seconds for it to slow done from
putting it into neutral.  I had the master cylinder replaced because it was bad
and we thought that was what it was.  I did get a letter from Toyota about the
law suit about the electronic throttle control.  Do you think that could be the
problem.  This is my only form of transportation and I am afraid to drive it.