> From: PB <pbrattan@gmail.com>
> Date: Mon, 21 May 2007 15:24:54 -0700
>
> I asked this question because the P.O. has just told me that the van
> got poor gas mileage - only 13-14 mpg!  [...]  I think I'll have to
> go through a few tanks to establish my mpg,

Definitely do that.  Try to use the same name brand and grade of
gasoline for each tank, and use the same refueling procedure each time.
If you can, try to drive in about the same conditions for each tank, or
at least remember that you spent most of one tank driving around
downtown and most of another tank out on the Interstate.

> but just for my own information, what would cause poor gas mileage in
> a 4 cylinder vehicle, other than constant use of power draining items,
> or a gas leak?

1) Driving habits
2) Driving habits
3) Driving habits

After that... underinflated tires, ignition timing set incorrectly,
ignition advance not working, coil/plug wires/rotor/distributor cap/
spark plugs worn, air filter clogged up, fuel injection system troubles
(bad sensors, vacuum/air hose leaks), internal engine wear, clutch
slipping (if so equipped), transmission problems (oil/fluid full?), CV
joint problem, bad wheel bearing, brake dragging (either mis-adjusted
or you forgot to release the parking brake), aerodynamics (driving a
Westy with the top up or hauling a parts Vanagon on the roof rack of
your running Vanagon), too many bodies in the trunk/Westy closets,
driving habits, etc...

Don't freak out at that long list, though.  A lot of times it's
something pretty simple and doing the normal tune-up things will fix it.

Matt Roberds