1985 Mercury Grand Marquis: common problems

Owners of the 1985 Mercury Grand Marquis filed 21 complaints with NHTSA, most often about electrical system and vehicle speed control. Details by component below, with sources.

Key figures

Owner complaints: 21

What fails most often

1 Electrical system 52% of all complaints
2 Vehicle speed control 19% of all complaints
3 Engine and cooling 14% of all complaints
4 Equipment 10% of all complaints
5 Engine 5% of all complaints
6 Fuel/propulsion system 5% of all complaints
7 Fuel system 5% of all complaints
8 Powertrain 5% of all complaints

Circle size and colour show each component’s share of NHTSA complaints. Schematic only, not a drawing of the exact model.

Electrical system: 11 complaints (52% of all).
Vehicle speed control: 4 complaints (19% of all).
Engine and cooling: 3 complaints (14% of all).
Equipment: 2 complaints (10% of all).
Engine: 1 complaints (5% of all).

Engines and transmissions

US-market versions per EPA. On the right: how many NHTSA complaints name this engine or transmission type.

5 L · petrol · 8 cyl
automatic, 4-speed

Drive: RWD

Symptoms owners describe

How many of the 21 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).

smoke, burning smell, fire8 · 38%
stalls while driving4 · 19%
A/C or heater2 · 10%
fuel system, fuel smell2 · 10%
jerking, harsh shifts1 · 5%
infotainment or screen glitches1 · 5%
unintended acceleration1 · 5%

Components owners complain about

Component	Owner complaints	involving a crash	Technical service bulletins (TSB)
Electrical system	11	0	0
Vehicle speed control	4	0	0
Engine and cooling	3	0	0
Equipment	2	0	0
Engine	1	0	0
Fuel/propulsion system	1	0	0
Fuel system	1	0	0
Powertrain	1	0	0
Structure	1	0	0
Tires	1	0	0

What owners report

Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.

While the contact's aunt was driving 40 mph, the vehicle stalled and all the warning indicators illuminated. The vehicle was towed to the residence where an independent mechanic diagnosed that the failure was due to no pressure in the fuel line and the fuel pump needed replacement. The vehicle was not repaired.
Engine · 2018-02-09 · NHTSA complaint #11071993
Vehicle has low power, stalls, always on high idle when started, transmission jerks, checked with dealer and they have no information on recalls although your data base shows numerous recalls concerning these problems. I purchased this vehicle from my father. He has never received a notice of any of the recalls.
Vehicle speed control · 2002-03-26 · NHTSA complaint #759772
Vehicle is stalling and has almost caused accidents, stalling possibly due to faulty tfi module.
Electrical system · 2000-11-20 · NHTSA complaint #557257
Cooper lifeliner classic steel belted radial tire p215 70 r15 experienced tread separation, causing damage to consumer's vehicle.
Tires · 2000-10-24 · NHTSA complaint #555572
When engine gets hot vheicle will stall, consumer must wait until it cools down to restart. Vehicle has been taken to dealer and mechanic several times, but cause is still unknown.
Engine and cooling · 2000-09-20 · NHTSA complaint #871037
Fuel line to the electronic fuel pump failed causing fuel leaking resulting in fire.
Fuel system · 1999-03-29 · NHTSA complaint #544544
Engine is so loud that owner can't hear radio or traffic approaching. Owner was almost hit by a police vehicle at intersection because he did not hear it coming.
Engine and cooling · 1998-11-13 · NHTSA complaint #830710
Sudden/unintended acceleration while being driven on freeway at 65 mph. Brought vehicle to a halt by applying the brakes and turning engine off.
Vehicle speed control · 1997-08-01 · NHTSA complaint #518185

When owners complained

NHTSA complaints by filing year. The peak shows at what age the problems show up most.

19951
19969
19972
19981
19992
20003
20021
20051
20181

Comparison

By complaint count this model year ranks 8,077 of 36,656 model years in the NHTSA data (top 22% most complained about).

On average one model year of the Grand Marquis has 117 complaints (34 years in the data). This year has 21, below average.

What to check before buying

Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
Vehicle speed control. Accelerator pedal, cruise control, throttle codes.
Engine and cooling. Radiator and fan after a frontal hit, coolant level and condition, overheating.
Engine. Cold start, unusual noises, oil leaks and engine codes.

Other years of this model

Questions and answers

What are the most common problems with the 1985 Mercury Grand Marquis?

Owner complaints to NHTSA most often mention: electrical system, vehicle speed control, engine and cooling. Total complaints: 21. The most frequent symptoms in complaint texts: smoke, burning smell, fire (38%), stalls while driving (19%), A/C or heater (10%).

How many service bulletins (TSB) were issued for the 1985 Mercury Grand Marquis?

NHTSA lists 0 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.

Should I buy a 1985 Mercury Grand Marquis from a US auction?

Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.

Other 1985 models

Read also

Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-05.