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 1990 Mercury Grand Marquis
1990 Mercury Grand Marquis
1990 Mercury Grand Marquis Problems
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.
Wear on the rear axle shafts near the bearings can create excessive play and lead to gear oil leaking past the seals. Gear oil will leak onto the brake backing plate, brakes, and wheels.
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.
1990 Mercury Grand Marquis Recalls (Recent)
1990 Mercury Grand Marquis Questions and Answers
this is the second tranny i am putting in it will not shift form low gear when driving there is no modulator on it but i have changed the speed control sensor i was told there may be a computer s...
when car shifts to 4th and you let off gas it quits pulling you have to give it a lot of gas for it to start pulling again already changed fluid and filter
when car shifts to overdrive and you let off the gas the transmisson kicks out of gear like it was shifted to neutral give it a lot of gas it starts working again 123 &reverse work fine only d...
Do these tensioners weaken with time, if not do the smaller serpentine belts stretch over time
1990 Mercury Grand Marquis Reviews
Hi i am 15 and this is my first car i paid $500.00 for it. it has a major gas and oil leak and had its tail pipe ripped off but, overall its a nice car. its got a 5.0 liter V8 in it. its extremly quiet for a V8 and with no tail pipe its still quiet.
its also got ajustable air shocks. a mini air compresser kicks on when it runs. i think its for the shocks but it could also be for the vacume system which runs the fuel injecters. any advice?
I REALLY DIDNT LIKE FORD OR MERCURY BUT THIS IS MY SECOND FORD PRODUCT AND IT RIDES SO SMOOTH IT LOOKS LIKE A LINCOLN RIDES LIKE A LINCOLN HAS ALL THE BELLS AND WHISLES.