runsrealfast wrote:
> I was looking at http://www.fueleconomy.gov/ and it rates my vehicle at
> 37 (city) and 40 (hwy).

Exactly which 97 civic do do you have? The 1.6 SOHC engine? Auto or
manual? Hatchback?

I'm looking at 1997 Hondas at that same website. None of the vehicles
are listed as 37/40.

The first entry is for a Honda Civic VTEC-E (FFS) with a 5 speed
manual. This is listed as 37/44. Is that the entry you are looking at?
This sounds very much like a Civic HX.

Well, is yours a 5 speed manual VTEC-E?

VTEC-E is Honda's mechanism for improving low-RPM engine efficiency.
That's why VTEC-E models have good mileage.

What happens under VTEC-E is conceptually simple: at low RPMs, one of
the two intake valves on each cylinder is nearly closed: it opens very
little compared to the other valve. This means that the fuel/air is
coming in mostly through one valve only, so that it circulates faster
and swirls around in the cylinder. It turns out that this good swirling
improves the combustion efficiency, allowing less fuel to be used.