I have a 1989 Mazda MPV mini-van with 206,000 miles on it. It ran fine until recently when the idle went from about 800 rpm to 1500-2200 rpm. Sometimes it idles up and down between 1900 and 2200 rpm when in park. Any ideas? It also seems to not break like before. It is getting harder to stop. I don't know if this is because of the higher idle or if the master cylinder or power booster is going bad. Any help would be appreciated

Suspect a possible brake booster diaphram ruptured. This would not only create a high idle speed due to a vacuum leak but also limited vacuum assist in the brake system. Does the brake pedal feel much harder to apply then before?