Six problems related to vehicle speed control have been reported for the 1996 Mercury Sable. The most recently reported issues are listed below.
While in park engine would idle at a very high speed. Also, while driving at any given speed vehicle will accelerate on its own, and it is very difficult to stop vehicle. Please provide any additional information/attachments. *consumer has not taken vehicle to dealership.
When vehicle shifts gears rpms stay at 1800-2000, will not go down, consumer has to shut off engine and restart. To dealer who replaced air bypass valve, then throttle positioner, coerrected problem for a short time only. Air bypass valve and throttle positioner sensor were replaced on warranty.
Vehicle speeds up when coming to a stop . Problem is sporadically. Manufacturer is unable to fix vehicle.
High idle when moving from park to drive, causing vehicle to lurch forward, and it will also travel couple feet if foot is not on brakes hard. Manufacturer issued a TSB, but it does not correct defect. Consumer states that this failure caused the liquid filled mounts to fail which also caused exhaust leak at manifold, the TSB number is 97-7-1, which states the pcm needed replaced due to an incorrect software identification block. Drive and serpentine belts failed.
Upon starting the vehicle, it accelerated at a high speed when the gear was placed in reverse. When this occurred, the vehicle lost steering power assist and brakes. The vehicle stopped when it hit an object. The driver then put vehicle into drive and turned the ignition off, but the vehicle accelerated forward. The vehicle then made several turns before stopping again. This failure occurred once before. The cause of the failure was undetermined.
When the brake was applied, the vehicle lunged forward and accelerated into some nearby trash cans and a wooden fence.