Mercury Sable 1999 Owner's Manual page 133

Roadside emergencies
3. Remove the jumper cable from the positive (+)
terminal of the booster vehicle's battery.
4. Remove the jumper cable from the positive (+)
terminal of the disabled vehicle's battery.
After the disabled vehicle has been started and the
jumper cables removed, allow it to idle for several
minutes so the engine computer can relearn its idle
conditions.
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