So I have a 2001 Civic and so when I went though the manual in the transmission section I saw the diffrence between D and D3.

"D - Use this position for
your normal driving. The transmission automatically selects a suitable
gear for your speed and acceleration.
You may notice the transmission
shifting up at higher speeds when
the engine is cold. This helps the
engine warm up faster."

"D3 - This position is similar
to D , except only the first three
gears are selected. Use D to provide
engine braking when going down a
steep hill. D can also keep the
transmission from cycling between
third and fourth gears in stop-and-go
driving."

So my question is, so in a stop and go situation would using the D3 position would be good for good fuel economy? Also since the fuel economy is stated for 28 MPG for City driving, is that based on using just the D position or the D3 position. Because in City driving you usually stooping and going