1999 Mercury Grand Marquis Throttle Position Sensors May Fail and Cause Engine Performance Problems

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.

Affected Model Years

This issue affects Mercury Grand Marquis model years 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001, 2002, 2003, 2005, 2006, .

77 people reported this problem

  • 1999 94,000 Miles
    my 2006 grand marquis mercury stalls. It will stall while sitting still, cruising on the enterstate and everywhere in between.the only thing consistent about the problem is that , I can traveled as much as 350 miles without A problems , then all of A sudden allthe dash lites come on and the car is power less. the dealership has changed A throttle body ($ 700+) the car stalled going home! Please, I need your inputs .

  • 1999 65,000 Miles
    Car will cut off going down the road, and it will start right back up, replaced fuel filter and went almost 800miles and it did it again. The other day it cut off sitting in traffic, but it always cranks back up??

  • 1999 238,220 Miles
    ENGINE WILL START ROUGH IDLE NO THROTTLE NOT RESPONDING RICH SMELL OF FUEL BEFORE DIEING TRYED TO RESTART WOULD NOT. NO CODES SHOWED UP TESTED T.P.S USING METER NOT RESPONDING UNLESS YOU TAP THE SENDING UNIT REPLACED EVERYTHING GREAT.

  • 1999 100,000 Miles
    bucks and hesitates around 35 miles per hour

  • 1999 160,000 Miles
    going down the road and car just quit running and will not start

  • 1999 0 Miles
    stalls, hard to start heistant all the time. when driving to speed up, heistant, got to push gas pedal couple times.

  • 1999 0 Miles
    car idles rough and stalls while running wont turn on for awhile then starts few minuts later

  • 1999 68,000 Miles
    did a full tune up weeks ago to mee it acts like a plug not firing i was thinking maybe egr or tps might be bad,,rough idle chugs down the road

  • 1999 83,000 Miles
    stalls at 20 miles kicks hard at 30 and then their is no issue. No power while accelerating, once it does start to accelerating it may start to jump even while foot is on brake. Cuts off in traffic all fluids are full.

  • 1999 115,000 Miles
    My car shuts off when I press on the brakes and when I try and make a turn, and it idles while in park or pressing on the brakes, some mechanic said it was a tps sensor and another said it was my maf sensor.

  • 1999 300,000 Miles
    Car stalls when driving will restart though

  • 1999 155,000 Miles
    itake maniflod blew i replaced it and new plugs. car ran fine for one day engine light came on and runs very rough. still not fixed

  • 1999 0 Miles
    my car has trouble getting into 1st gear

  • 1999 145,000 Miles
    misses going down the road or sitting know all the timelike for a flash

  • 1999 125,000 Miles
    Idle problems, stalling, warmup problems, would have replaced idle air control valve if the car had one.Of course, with its fly by wire throttle, it does not. Replaced tps sensor after testing and inspection upon removal. Old sensor was wollered out. Important note- machine screws that attach sensor are lock tighted on and require some heat to remove without snapping off. Heat gun works fine.

  • 1999 0 Miles
    It want crank it will sit a few days and then start back up it will run a few days and then won't crank the next couple of days what is wrong with my car

  • 1999 0 Miles
    have stall in engine

  • 1999 140,000 Miles
    Cleaned sensors

  • 1999 101,000 Miles
    Rough idle, Hesitation on acceleration, Terrible terrible gas mileage. I've owned 3 of these Grand Marquis LS 1998, 2001, 2002 and never had a problem until this one 2001.

  • 1999 142,000 Miles
    Car stalls while idling and upon taking off after sitting mostly at lights, then my check engine light comes on and without warning will stall. I lose my power steering when this happens. I pull over and turn key off and then it restarts right away again. Been doing it for two years now, but getting worse