Cruise Control problems of the 2006 Ford Ranger

Run away engine after using cruise control. The cruise control has not functioned for the last 1. 5 yrs. The on light will come on but it won't set. It went out ,but after it stopped working the engine accelerated briefly without the cruise control activated but we had pushed the on button to see if it worked. This also occurred a second time after turning the cruise control on and of. The first two episodes weren't too bad and the vehicle rpm slowed down after the brakes were applied. Just this last week I tried the cruise control again to see if it would work and it didn't. Aprox two days later while coming to a stop and not using the cruise control the engine raced while approaching a stop light. I had to stand on the brakes to keep from going thru the light. I finally placed the transmission in neutral and the engine was still racing. This ended after a few seconds. I was standing on the brakes the whole time. Let me be clear, this has happened three times with the last time 1. 5 years ago being the worst. It started occurring after the cruise control wouldn't turn on and then one day suddenly did after hitting the button. Each instance occurred a few days after trying to get the cruise control to work. All three episodes occurred without ever touching the cruise control during the day that the engine racing occurred.