Self-suffering is nature's way of heightening our appreciation of happier moments.

Most people satisfy their quotas through bad marriages, high-impact aerobics, tofu fajitas, variable-rate mortgages or moving to Cleveland.

Others buy Jaguars.

That personal philosophy was reinforced shortly after the 1992 XJS convertible--all seductive bulges and whippet lines in Haagen-Dazs vanilla--was delivered for review.

Three miles into the test, the throttle linkage collapsed.

We'd been growling across midtown--and actually recalling a press release on the new reliability of the Jaguar since Ford became its guv'nor--when everything let go.

The car's mighty V-12 jammed full open and a 263-horsepower stampede began building on 3rd Street.

One option would have been to disturb late afternoon foursomes by crashing a fence and broadsiding across the back nine at the Wilshire Country Club. Better, however, to slap everything in neutral, switch off the ignition and, sans power assistance for brakes or steering, waddle clumsily to the curb.

A quick grope beneath the hood located a disconnected turnbuckle on the throttle linkage; a Swiss Army knife and finger tightening provided the temporary solution.

The subsequent horror among Jaguar publicists sounded permanent: "Somebody didn't tighten that nut back down at the port or at our engineering facility in Phoenix," explained Jaguar spokesman James Groth after the car had been examined. "The problem hasn't shown up with any other car. It was an isolated incident, absolutely."

Isolated or not, failure of a dime part on a $67,500 luxury car is inexcusable. Any breakage that likely would send a panic-prone driver careening through Nordstrom's is indefensible.

Yet, herein lies the colossal, unfathomable oddity of Jaguar: No matter the severity or inconvenience of the mechanical collapse, Jaguar owners will defend their cars to the crusher gates. They will forgive the unforgivable and explain the inexplicable.

Because when a Jaguar is running right, there simply is no fuller satisfaction, no firmer return to the elegance of yesterday and nothing quite as soul-stirring as a fast run in the big cat. It roots a driver in that Golden Age when styling didn't change every 12 months, engines were developed more for muscles than finesse and a few bad mechanical manners were all part of the experience.

It is front-engined and rear-drive.

It is a two-seater and a drug.

Costly? There is a Santa Monican who recently had a 30,000-mile checkup on his XJ6 and paid $498 to be told there was absolutely nothing wrong with the car. He's says he is shopping to buy his third Jaguar.

Another individual once owned a Mk VII that snapped two very expensive half-shafts in its first 15,000 miles. He traded it on an XK140 with electricals that suffered regular meltdowns. And I'd buy another Jaguar tomo rrow.

The new XJS grand tourer--breakaway throttle and all--is no less addictive.

This is the first major revision of the XJS series (the 12-cylinder convertible and coupe, with a 6-cylinder version of both in the pipeline) in 16 years. Jaguar says the face lift involves 1,200 parts, 40% of the body panels and styling amendments that are "significant in scope."

The visible differences are minimal. A new front end offers a revised grille with two large headlamps instead of four smaller ones. The redesigned rear end has wraparound taillights with something called "neutral density" lenses. That means the stretch of glassware shows Ray-Ban gray until brake, rear and back-up lights activate. The aesthetics of this will escape everybody.

Not so the interior. Richly polished wood trim has moved closer to the excessive. Instrumentation has reverted to the traditional layout of two large main dials. Seats have been completely redesigned, power adjustment as finally been added with multiple settings (and a two-position memory) controlled by a door-mounted switch pack.

Flow and sensitivity of the climate control has been upgraded with air swirling consistently, immediately and everywhere. The audio system is a six-speaker Alpine, and now there's an optional CD system. Most of the switching functions have now blessedly been transferred from dash to steering wheel stalks.

But we do wish that Jaguar had decided to redesign the slender "T" it calls a gearshift. The construction is too thin, the heft too delicate for the thundering nature of the car. It feels like a surgeon's retractor.

The convertible top is kid's play to raise and lower, and securing the canvas cover is a gentle tug and a snap. With the canvas up, wind noise is minimal.

Underneath the hood is Jaguar's impressive V-12, which is directly descended from the company's racing engine. The output--263 horsepower from 5.3 liters--remains unchanged. But a new fuel-management system smoothes and hastens delivery of that power.

All of which sounds like Jaguar has gone to great lengths--to say nothing of expending $81 million--to remain perfectly old-fashioned for 1992.

Or as Michael Dales, president of Jaguar Cars Inc., explains: Whenever styling of the XJS has been submitted to independent designer clinics and customer focus groups, the combined approval is an incredible 98%.

It wouldn't be prudent, adds Dales, to muck about with such a good thing: "What we've got to do is take what is already seen as very, very successful styling . . . and add to it some polishing and some updating and refining."

This year, a 43%slump in global sales might indicate the fallibility of Jaguar's dedication to planned classicism. Not so, say officials. Like every other car maker, imported or domestic, economy or luxury, the company is being throttled by the recession.

And, they say, Jaguar fully intends to continue its homage to yesteryear.

That's why the twin ashtrays on the center console seem to wear two millimeters of chrome and clang shut like the back door to Bank of America. The gas cap is huge, visible, bronze, heavily chromed and could easily be a two-handed operation.

Lesser cars stamp out their parts and rely on machine finishing. With a Jaguar, most parts are still forged, and Jaguar's final assembly "robots" leave fingerprints and drink tea.

Mercedes and BMW engineer superb, high-performance, grand touring coupes with V-12 engines. But neither motor, frankly, can hold an inspection light to the broad-shouldered power and lusty snarl of Jaguar's V-12.

And Jaguar brings its 12-banger to market for $10,000 less than the BMW 850i and $50,000 less than the new Mercedes 6.0 liter S-Klasse.

Not that the XJS is flawless.

Staying glued to yesterday's purity keeps the car heavy, large and ponderous. An adroit sports car it's not.

A decent suspension sets the car flat during high-speed touring. But bend it quickly at those speeds and the car's very noticeable bustle and relatively short wheelbase--a full 4 inches shorter than the BMW 325i--sets the whole dipping and pitching.

And gas consumption--an EPA city-highway average of 13-17 m.p.g. for the convertible--is an environmentalist's nightmare. Also the reason for a $3,000 gas-guzzler tax.

Yet the XJS remains a classy car. Yes, it is several design years behind the times. But that is precisely what imparts a huge sense of distinction. Yes, it is expensive to obtain, costly to maintain and still mechanically unfaithful after all these years. But think of it as a Victorian house.

No matter the shaky plumbing, we all want to live in one.

1992 Jaguar XJS

The Good Instant classicism and grandest of tourers. Quality components and equipment. Lowest-priced V-12 on the market. Totalco fort.

The Bad Still short on reliability. Heavy and large. V-12 thirst.

The Ugly Is that a gearshift or a dipstick?

Cost Base, and as tested: $67,500 for convertible, $60,500 for coupe. (Includes BBS lace alloy wheels, anti-lock brakes, driver's side air bag, leather seats, automatic climate control, burl elm trim, power seats, etc.)

Engine 5.3-liter V-12 developing 263 horsepower.

Type Rear-drive, two-seat, grand touring convertible.

Performance 0-60 as tested, 8.7 seconds. Top speed, estimated, 142 m.p.h.

Curb Weight 4,194 pounds.