The throttle position sensor (TPS) may fail. Common symptoms of a defective TPS can be rough idle, hard starting, hesitation on acceleration, poor fuel economy, and stalling.
Resources for the Repair and Maintenance of your 1991 Mercury Grand Marquis
1991 Mercury Grand Marquis
1991 Mercury Grand Marquis Problems
A spring in the seat belt buckle may wear or fail, causing the airbag light on the instrument panel to illuminate. Failed buckles will require replacement.
The EGR valve position (EVP) sensor can fail on this vehicle. The EVP sensor measures the EGR valve position and transmits the date to the engine control computer. If it fails, drivability and fuel economy can suffer, the Check Engine Light will commonly illuminate.
If you experience difficulty starting the engine when cold, stalling at idle, or hesitations during acceleration, it may be the idle air bypass valve. This valve helps the vehicle idle steady when the accelerator pedal is not pressed.
It is not uncommon for the intake manifold and/or valve cover gaskets to develop a coolant or oil leak. Leakage from the intake manifold may result in coolant in the engine oil. Coolant mixing with the engine oil severally impacts the lubrication ability of the oil. Internal engine may result if this condition is not repaired promptly.
1991 Mercury Grand Marquis Recalls (Recent)
Summary: THREADED INFLATOR COMPONENTS MAY HAVE BEEN DAMAGED DURING ASSEMBLY WHICH MAY ALLOW COMPONENTS TO SEPARATE WHEN INFLATOR RECEIVES A SIGNAL TO DEPLOY THE AIR BAG.Learn more »
1991 Mercury Grand Marquis Questions and Answers
The engine on my car has been shutting off when I take off my foot from the accelerator. It doesn't happen immediately. I will press the brake pedal and shortly after the car will turn off. Th...
i am trying to revive a 1986 mercury marquis. drained all bad gas out. put ten gal. of good gas in. put gas in throttle body to prime it. it starts but wont stay running. can hear the fuel pump kic...
1991 Mercury Grand Marquis Reviews
Bought this used with just under 100,000 miles on it. Not running right when I purchased it but did some work to it and it's been a very good car. I beefed up the rear suspension with coil over shocks and Moog cargo coil springs plus the addition of a police rear sway bar (badly needed for these large cars). I would like to stiffen up the front suspension and it would be a pretty nice handling vehicle for it's size. Nice to see Ford made the steering box a quicker ratio over the old 4 turn lock to lock boxes.
ilove this car
my tranny has reverse but no forward gear does it need to be rebuilt or just an overhaul? Other than that i love it only has 34,500 miles.
A great Ride anywhere, Highway or across town. They dont make them like this anymore. A great family car with plenty of room.