ISTR that the priec of Detroit muscle bubbled up and went poof once
before -- in the early 90s, if memory serves.  Speculative markets are
inherently super-risky.  Unless you're really astute about buying low
and selling high, and willing to stay on top of things so that you
know when to jump off that ride, stay away from old cars as an
investment -- buy them only because you like them, and be ever mindful
of non faddish models that would give you satisfaction similar to the
craze du jour for a lot less money.

Digging even further into memory, we find a Popular Mechanics (or
somesuch) retrospective on the history of the V8, from another climax
of gas prices in the early 80s.  At its conclusion, someone is in his
garage sometime in the future, starting up "the 454 Chevelle he's been
faithfully anointing for decades" just to listen to "a sound like the
beating of a thousand angels' wings..."

I wish I could remember when that putative future was supposed to be,
and wonder if it's around now.

That had a lot to do with said concluding image.  Of course, at the
time, people thought there would be a third wave of the energy crisis;
instead the OPEC nations decided they'd rather bicker among themselves
than hoover our wallets, and oil prices went on a long plunge to
inflation-adjusted historical lows.    However, OPEC or at least less
formalized instantiations of the general concept  were too good an
idea to stay down forever...

Not quite sure I have anything approaching a comprehensive
understanding of the market forces that push diesel to higher prices
than gasoline, when intuitively one thinks of the heavier petroleum
fractions as being cheaper and more readily available.  I am reminded
of a Wall Street Journal article from a few years ago, about a study
which noted that crude prices had become dominated by futures
speculation and were no longer strongly and directly coupled to supply
and demand (they seemed to nod with approval at this sign of oil's
finally achieving maturity in the commodity pits).  I wonder if this
is true of refined products as well.  This  page suggests, however,
that growth in demand worldwide, combined with a US transition to
ultra-low-sulfur diesel, has been a main driver for diesel's price:
http://www.eia.doe.gov/bookshelf/brochures/diesel/  Also, diesel might
compete more directly with other uses, such as home heating oil, than
does gasoline.

Diesel passenger cars never caught on in the States as they did in
much of the rest of the world even after the technology of small
diesels available here got better in the mid-80s  -- a combination of
cheap gasoline and the woeful GM diesel V8s of 1970s vintage, I reckon
-- though they've long been available here, from foreign makers that
had a home-market base for a good diesel passenger-car engine
(Mercedes, VW, BMW, Isuzu, Peugeot...)  I think Mercedes and VW have
been the only ones consistently able to keep the things on the
market.    (In recent years, pollution rules -- aimed particularly not
at the stereotypical black smoke, but invisible particles, from
diesels -- have emerged as another damping factor.)  It must have been
frustrating for the manufacturers to ride this popularity roller
coaster tied to gasoline-price fluctuations, plunging  just as they're
getting settled into the market.

Pickup trucks have become the great exception.  The Cummins
turbodiesel in Dodge pickups was bellwether of a new generation of
diesels from all three major manufacturers that over the last 10-15
years has become very common.  This makes sense when you think about
it -- diesels scale up more easily and rewardingly than they scale
down, and lend themselves more readily to that usage and driving
style.  Also, you don't pay nearly the mileage penalty when you start
towing or carrying a heavy load that you would with gassers.
Heavily built and well designed and maintained ones can also soldier
on for a very long time.

One thing about diesels, though -- as others have pointed out
recently, they can be run on ersatz fuels, notably biodiesel (from oil
recycling or from biological processes).  This might influence their
sustainability in some future scenarios.  Also, it has about ten
percent more energy content than gasoline, and another  nontrivial
percentage more than gas/alcohol blends, so all else being equal,
you'd be going further for the higher price.

--Joe

The problem is the old saying... speed costs money how fast do you want
to spend?