1997 Jeep Grand Cherokee cruise control problems

I was parallel parking the car on my residential street. I was in reverse and proceeded to back into the parking space. The cars both in front and behind me were some distance away. Suddenly the engine reved to a very high RPM and the car shot forward and crashed into the car in front of me. The car was still in reverse when I turned off the ignition. Several persons witnessed the incident. They heard the high rev of the engine, and also noted that the backup lites were on when I hit the car in front of me.

When I stop with the brake firmly applied the engine surges sometimes and dies. If I put it in park and it will restart and I can proceed. This happens at traffic signals, when stopped, waiting to turn, etc.