Ford (and its luxury division, Lincoln) has had an unfortunate history of thinking up some really great ideas - and then not following through on them.

From the recently euthanized and now-resurrected Taurus to the abandoned Mark VIII luxury coupe to the died-from-neglect BMW contender Lincoln LS sedan. All of these vehicles were either very popular initially or had tremendous potential. And all were left to fade away into near-irrelevance while competitors ate into their market share.

The Navigator is on that sad-sack list, too.

At the time of its launch and for several years thereafter, it was the pre-eminent full-size luxury SUV - having virtually created the segment and inspiring a slew of imitators, including the Cadillac Escalade. The Navigator was once so white hot, in fact, that on the strength of Navigator sales alone, Lincoln actually surpassed Cadillac in overall sales for the first time in decades.

But Lincoln let it all go to seed by not updating the Navigator to keep pace with upstarts like the Escalade - which kept getting better with each redesign. Today, the Escalade owns the slot once held by the Navigator with a dominance akin to Mike Tyson at his prime.

Lincoln's just now picking itself off the floor before the ref calls the fight for good - hoping it can recover the prestige (and buyers) its full-size luxury SUV once had.

Unfortunately, that goal may still be out of reach.

On the upside, the Navigator did get a thorough refresh for 2007 and is now available in both standard and optional long wheelbase L versions - with the L version being 14.7 inches longer overall than the standard model. This provides an additional 25 cubic feet of storage capacity (42.7 cubic feet. vs. 18.2 cubic feet) and gives buyers who need schoolbus square footage the space they need. With both the second- and third-row seats folded, the standard wheelbase model offers 103.5 cubic feet of cargo area; the L model ups that to 128.2 cubic feet. Seven (even eight) passengers can now ride in the Navigator - and with all their stuff, too.

The ride is also much-improved.

Modifications to the chassis are extensive and highlights include a new, wider/stronger boxed steel frame with a fully independent, five-link rear suspension (vs. the tough but primitive solid axle design used previously), combined with a lower center gravity designed to smooth out ride quality over uneven terrain and make this super-sized SUV (and at 5,872 pounds without passengers on board, "super sized" is no exaggeration) less boozy-feeling during cornering.

Though it retains body-on-frame construction and is available with a real-deal four-wheel-drive system that includes a transfer case and locking differential, the kinship between the '08 Navigator and the pick-up trucks it is descended from is no longer kissing cousin-close. Like virtually every other premium SUV, evolution is taking the Navigator down a different branch of the Darwinian tree. Technically, the Navigator could still be taken "off-road" - but its gradual transformation from live axle to IRS (and so on) reflects the well-known reality that few of these chrome-wheeled, leather-wrapped on-road titans ever leave the pavement. And that's all to the good, probably - since the shift in-design emphasis has resulted in a vehicle that's much better-behaved negotiating the affluent suburbs it was born to prowl.

The new Nav's brakes have also been updated - with larger, thicker rotors to help dissipate braking heat more effectively and make them less fade-prone, as when descending a long grade and the driver is riding the pedal to keep the behemoth from needing one of those "runaway truck" lanes. Revisions to the hydraulics and boost assist provide a firmer, more consistent feel through the range of pedal travel, too. Road noise at highway speeds has been dramatically cut back through the use of thick-cut exterior glass and the adoption of a new six-speed overdrive automatic transmission with two steep overdrive gears - designed to curb drivetrain noise by cutting engine RPM to a fast idle, even at 70-something MPH.

Here again, a clear improvement over previous Navigators.

The safety package is also comprehensive and includes standard three-row curtain air bags, Advance Trac traction control, a rollover-sensing electronic stability control system and knee-impact padding for the front-seat occupants.

No complaint there, either.

Eighteen inch wheels are standard on the Luxury version - with rap-mogul-friendly chromed 20-inchers available optionally. Top-of-the-line Ultimate versions (either standard wheelbase or extended L versions) offer the amenities you'd expect, including power folding third row seats, power lift gate, heated and cooled front seats, sunroof, etc. Power running boards, a 600 watt THX premium audio system with 14 speakers, MP3 capability and Sirius satellite radio hook-up and a rear-seat DVD entertainment system with 8-inch screen and wireless headphones can be ordered up.

The new interior is another area worth praising; it's certainly as soft and opulent as it ought ought to be - with a a much more distinctive (and Lincoln-specific) retro-themed design than the previous Navigator, which didn't do a very convincing job of hiding its Ford Expedition roots.

But there is a potentially fatal flaw that could undo everything. And you'll find it by raising the hood - or pressing hard on the gas pedal. The '08 Navigator comes with just one engine choice - and it's the same 5.4 liter, 300 horsepower V-8 that's also used in the Expedition.

You might ask: Isn't 300 horsepower sufficient? Five years ago, it would have been. But tin 2008? When arch-rival Cadillac Escalade comes standard with a 6.2 liter, 403 horsepower engine?

End of discussion. It's not even close.

A 103 horsepower deficit in a vehicle whose very essence is vehicular one-upmanship undermines the whole package. It doesn't help at all that the 5.4 liter engine isn't even exclusive to the Navigator.

Buy a Cadillac, and you get more than you'd get in a Chevy Tahoe - or even a GMC Yukon, for that matter. More cubic inches, more power. It's expected - and reasonable to expect it, frankly, given the price uptick. But the guy who pays top dollar for a Navigator isn't getting any more underhood bang for his buck than the guy who saved himself a ton of money and bought an optioned-out Expedition instead.

Sure, the updated Navigator came out of the shop with a six-speed automatic transmission that neither the Mark LT nor the Expedition received initially. But which will buyers be more likely to notice? The extra gears on top?

Or the 103 horsepower that's missing?

My teeth hurt at this point; I can't understand what "they" (the Lincoln product planners) were thinking. It makes no sense at all. Three hundred horsepower is barely competitive in the mid-sized, non-luxury SUV segment these days. In the full-size, ultra-premium segment, it's inadequate - prestige-wise, at least. And prestige is at least part of what you're paying $50k (or more) for.


How can the Nav compete with the Escalade and other top-tier SUVs - let alone stand out - given such a gaping underhood deficit?

Any comparison here leaves the Lincoln looking weak. Its overhead cam engine is smooth and quiet, yes - and the spec. sheet says you can pull 9,000 pounds. But out in the real world, 300 horsepower is so-so at best when chained to the near six-thousand pound mass of the standard wheelbase version. And it's hurting when tasked with pulling the even heavier L extended wheelbase version.

It's true the base price of the Navigator is around $10k lower than the base price of the Escalade ($45,755 vs. $56,775). And you could equalize things, power-wise, by adding a supercharger to the Navigator. But that's a hassle, voids the warranty - and you're still only just par with the steroidal Cadillac.

Lincoln may have a glass-jawed contender on its hands.

At minimum, the Navigator may be at a huge competitive disadvantage. At worst, it will bomb because buyers expect more of a vehicle that was once the clear leader in its segment - and which, unfortunately, still hasn't got the goods to play ball with the usurpers who have taken its place.