1990 Mercury Grand Marquis Repair and Maintenance
A guide to problems, costs, maintenance and repair for your 1990 Mercury Grand Marquis
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1990 Mercury Grand Marquis ProblemsEngine Performance Problems Due to Failed Throttle Position Sensor
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.
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.
1990 Mercury Grand Marquis QuestionsMy car has no spark and no power to fuel pump why changed coil solenoid ignition (1 answer)
I drove my car home from work was fine an hour later wouldnt start. I changed ignition switch, solenoid, coil, cut out wires with cracked insulation got power to coil but no spark coming out thats y i changed coil. wires in harness to module under dist. Cap were bare and touching so i checked fus...
1977 mercury grand marquis