1998 Mercury Grand Marquis Misfire due to failed spark plugs or ignition coil

Bad spark plugs or an ignition coil can cause ignition misfire, which will illuminate the Check Engine Light .

Affected Model Years

This issue affects Mercury Grand Marquis model years 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, .

68 people reported this problem

  • 1998 172,000 Miles
    Had Crack Intake but Replace; Also put new spark Plugsand #4 and #2 coil packs in. but still having skipping issues

  • 1998 150,000 Miles
    engine (chugs)misses at times new plugs / fuel filter have not helped

  • 1998 167,988 Miles
    Had a stalling problem, that went away, now it chugs and has a misfire, plus gas caused the stalling when I went back to regular it didn't stall, P0304 cylinder 4 misfire.

  • 1998 0 Miles
    Replaced coil and sparkplug but still have a cylinder missing. Intake gasket bad?

  • 1998 135,000 Miles
    Sputters really bad check engine lights on 2 misfires

  • 1998 157,000 Miles
    Number 2 cylinder misfire

  • 1998 150,000 Miles
    Yup. Runs great at high rpm. But lil shake in the motor at idle

  • 1998 52,000 Miles
    Having misfiring from plug number 4. It happen after putting gas in car. It ran great until I filled it up.

  • 1998 80,101 Miles
    one morning the check engine light went on and the car rode rough. I figured bad gas or fuel filter. 2 miles on the check engine light started blinking. Call to mechanic told me to get the car to him ASAP. Drove 6 miles home going 10mph on the shoulder, praying all the way. Bad ignition coil. He replaced all the plugs. Got off cheap, could have been catalytic converter or worse. Otherwise great highway car.

  • 1998 145,456 Miles
    Took the car on a 1,200 mile road trip, about 400 miles left on the return home the car started to vibrate / chug. I wasn't sure if it was a fuel or spark problem or if it was the transmission. At first it was very noticeable while accelerating over 55 MPH or while going up hill, the transmission seemed like it wasn't sure if it wanted to be in overdrive or lower. I assumed it was a lockup torque issue. The odd part was I could kick down to a lower gear (accelerator to the floor) and the engine would seem to smooth out. That's why I assumed it was a transmission issue and not a fuel / spark problem. The further I drove the worse the engine ran, even now it runs poorly at idle. I just got into the shop and they tell me the codes say there is a misfire on cylinder 1 and 8. I believe it is an injector issue due to the fact that the issue is progressively getting worse. I believe if it was a coil pack (spark) it would pretty much remain the same at all times. Guess I'll know once it is fixed.

  • 1998 0 Miles
    Misfiring plugs or coils. Advance Auto put a tester on it and said 2 of my coils were misfiring. I am in the process of changing the plugs and all the coils. I found 8 coils online for 125.00 new. The car has 256,000 mi on it

  • 1998 217,000 Miles
    Misfire during highway driving and going up a hill. Went to local mechanic to verify autozone codes, cost $ 60. Went to autozone and bought coil pack for $ 68. Fixed with buddy.

  • 1998 134,000 Miles
    Check engine light came on. Did tune up. Check engine Light on after week. Checked at auto zone indicates ignition coil is the problem now

  • 1998 200 Miles
    coolant leak and or thermostst bad. fouls 5th cyl. spark plug good but replaced. need to do coil. maybe worped or cracked heads?

  • 1998 119,332 Miles
    Not fixed. not sure this is the problem

  • 1998 204,000 Miles
    When driving over 60 miles/ hr, noticed hesitation in running, took to deal who confirmed two coils and spark plug need to be replaced

  • 1998 179,000 Miles
    Damp weather # 6 cylinder ignition intermittent ODB ENG LIGHT, P0306 on ODBTEST METER

  • 1998 122,000 Miles
    Car felt sluggish and check engine light came on. OBD reader stated it was a misfire. Engine Coil got replaced. Has not fixed the problem. So I'm going to buy every spark plug and engine coil needed and see if it fixes the problem

  • 1998 155,500 Miles
    My check engine light came on and I was feeling some lack of performace, like the motor was trying to hesitate or miss some power

  • 1998 101,100 Miles
    Spark plug on 5.4L V8 engine misfiring causing it to be ejected from engine.