2006 Honda Civic DX-G Throttle-by-wire
 

I got a manual transmission 2006 Civic DX-G at the end of May, and have
since put on over 10500 Km. During that time, I have averaged 6.87
Litres/100 Km on the whole 10500 Km, 5.71 on a 3000 Km road trip and as
low as 5.24 on some sections of the road trip. So I certainly have no
problems with the gas mileage.

However, since I first got the car the throttle has produced a slight
jump between acceleration and deceleration (feels like an automatic
transmission shifting), rather than the smooth ability to set a speed
that I have been used to on other cars (all non-Honda).

You notice this the most trying to maintain a steady speed on downhill
sections. Backing off on the throttle slightly to maintain speed results
in a slight notching of the engine into engine braking. As the speed
drops, a slight increase in the throttle, to maintain speed, results in
a slight jump in the engine, and the speed rises too high. There appears
to be a small area of the travel of the throttle so that slight changes
in the throttle position do not change the engine speed, at a constant
load, but moving past this point will jump the power up or down (sort of
like a point of histerysis in the power curve).

During the road trip I noticed that it was difficult to maintain speed
as terrain changed, and slight changes in slope, insufficient to require
engine braking to hold speed down, could have significant changes in
road speed, if you were not continually watching the speedometer, in the
range of more than + or minus 10 Km per hour at a road speed of around
100 Km per hour. This required a higher driver attention load to stay
around the speed I wanted to be going. I saw a lot less of the scenery
than I would have in any other car I have had.

The questions I raise are:

1. Should the throttle have this "shifting" effect, or should it be a
smooth transition of more or less power.

2. Should the car speed range through such a wide range without constant
attention, with slope changes small enough to not really be noticable to
the driver?

And if this effect is not normal, what could be done about it. I have
already mentioned this to the dealer, who had it road tested, and
indicated that it was normal for a manual transmission.

Tom