1999 Jeep Grand Cherokee engine problems

99 jeep grand cherokee with engine problems customer states that the rpm's would immediately go up to the 200 or sometimes higher as soon as he starts up the car and also accelerate when the brakes are applied* the consumer stated various parts were replaced, however the problem returned. The consumers wife was driving, when all of a sudden the vehicle started to accelerate on its own, she applied the brakes as hard as she could, however the vehicle continued to proceed in a forward motion.

Within the last 6 months my jeep's engine has shut off" while driving" at various speeds 5 different times but not exceeding 60MPH. Four of the six times I was able to shift into neutral and restart the engine, two times I had to wait approximately 5 minutes before it would restart. The incident at 60MPH happened on a 4 lane highway and luckily I was close to the shoulder when it shut off and I was able to get it off the road before the steering locked up and no one was hurt.