One problem related to crankcase (pcv) has been reported for the 1996 Mercury Sable. The most recently reported issues are listed below.
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.