Within a week of purchase, I had ignition misfiring. Dealer serviced under warranty. A week after I finally got it back, same problem. This time, they replaced a cracked valve cover; dealer covered under warranty.
The car has a terrible vibration around 55+ MPH. The dealer balanced and rotated the tires under warranty. This somewhat alleviated the problem, but never eliminated it. The car would always have a vibration or steering wheel shake at high speeds.
Around 57,000 miles (Late Winter 2004/2005), the neon center light failed. The part was $400+ and I replaced it myself. Note that this part is now obsolete and you may not pass inspection without it if your state lists it as part of the brake light/ safety system.
At wide-open throttle or aggressive driving at highway speeds, I would smell a rotten egg odor as if the catalyst had failed. The problem was intermittent and probably costly- so I never bothered to have it checked.
This car had lousy gas mileage. I could never average more than 19 MPG (75% highway). My 1996 Mark VIII never averaged less than 22.5 MPG- same commute.
The heated seats died around early 2005. Dealer informed me that the parts were discontinued- but listed for around $125 per side. Too bad- I really enjoyed this feature.
OEM Battery failed at 60,000 miles in Spring of 2005. $80 for a new high-cranking Motorcraft battery.
Vehicle leaked small amounts of motor oil. The oil filter adapter gasket failed. This is a common problem on all 4.6 motors. $10 part, one hour of my own labor, hand tools, extensions, and dozens of cuts on my hands later- it was repaired.
Around 75,000 miles around the late-Spring of 2005, the lightning control module went haywire causing the interior lights to stay on when the car was running. This was very distracting for night driving. The part costs $750 and must be installed by the dealer since it ties into the PATS anti-theft system. They must reprogram the key after installation. I elected to remove the interior lights as opposed to waste my money.
Around 73,000 miles in the Summer of 2005, the stock JBL amplifier died.
Around 76,000 miles, a spark plug blew out of the cylinder head. I needed a new coil-on-plug ($55) and spark plug. I had a mechanic friend thread-sert the spark hole and I replaced the COP in about 10 minutes myself with basic hand tools.
By the time I sold the car around 78,000 miles, the car needed a new upper control arm.
This is one of the nicest-looking cars on the road. The 1997-1998 Generation-II Mark VIII had a great light show; HID lamps, neon tail light, and illuminated side mirrors. It looks fairly aggressive, yet luxurious. There aren't a hell of a lot of these on the road, so it turns curious heads.
The handling is pretty good for such a large car. This vehicle has an independent rear suspension that handles with the accuracy of a sports car, yet maintains luxury car comfort.
Acceleration is excellent. The transmission shifts nicely. Cornering and aggressive handling are good for the size of the car.
The interior is very comfortable and easy to clean. The quality of the leather is very good and will last of you maintain it. The dash and this car have some nice features: digital information center, fuel computer, oil life monitor, and an overall system check that detects bad bulbs, fluid levels, air suspension problems, and miscellaneous problems that might occur.
The car can be a PITA to maintain; a great deal of parts including HID lights have been discontinued and can get expensive if you don't know where to shop for parts. This car can nickel-and-dime you to death- so if you plan to purchase, bring your wallet. Maintenance items such as the oil filter and thermostat are a mission to replace!
Considering that parts are being discontinued and the operating and dealership costs can get out of hand, I cannot recommend this car as a daily driver or commuter vehicle. If you can find a low mileage Mark VIII in a rare color, or Collector's Edition; or you want a unique high-performance weekend warrior- go for it. Otherwise, shop around before you buy.