RepairPal Certified shops can diagnose and repair your 1991 Mercury Grand Marquis. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
1991 Mercury Grand Marquis why is my oil light coming on when i come to a stop
Internal engine wear causing low oil pressure or the oil sending unit 'might' be the culprit... Suggest oil pressure test to see what actual pressure is.