Choosing a replacement plug
1 of 2Single platinum plug
The basic, least expensive plug will work, but not as well.
2 of 2Double platinum plug
A little extra money buys better engine performance.
Choosing new
spark plugs isn't
as easy as it used to be—dozens of choices
are available. Here's
what you need to
know:
Tip 1: It's best to
stick with the types of
plugs you rode in on.
The car manufacturer
may have originally
installed plugs made
with precious metals.
Platinum, yttrium
and iridium plugs are
more expensive than
traditional plugs, but
the coatings provide
much better wear
resistance and maintain
their gap longer.
Never downgrade to
a less expensive plug.
Your savings will be
quickly offset by the
shorter service life
and reduced gas mileage.
Consult your
owner's manual or
ask the auto parts store for the manufacturer's
recommended plug.
Tip 2: Some plugs have adjustable-plug
gaps and others have a fixed gap,
but gap is always important. If the store
recommends a fixed-gap plug, check
your owner's manual to make sure it's
the correct gap. If it isn't, find another
brand. If the gap is adjustable, make
sure you check (and adjust if necessary)
the gap on each plug before
installation.
The auto parts store computer
showed eight different plug choices for
a 1999 Ford Taurus. Prices ranged from
$1.79 for a traditional plug to $14.99
for iridium. We chose the $2.79 double
platinum type because that's what had
been installed at the factory.
