While sitting in idle the vehicle will rev up on its own, rpms will increase greatly, vehicle will actually lunge forward due to the very high idle. idle will then drop and sometimes cause the vehicle to stall. vehicle will then not start properly. once restart does occur, vehicle will jerk when put into gear. acceleration is then very slow while rpms are still running very high. while driving rpms will then drop and vehicle will jerk before the rpms rise again. this causes very poor mileage as well as unsafe conditions while at a stop or driving. this occurs intermittently. has been checked numerous times by different dealerships and independent mechanics, however, problem is so intermittent that a diagnosis has yet to be correct so no solution has been found as of this time. problem has occurred off and on for 2 years and is very frustrating. *tr