I am seriously considering to buy either Mazda 3 or Mazda 6 (if the latter can be gotten for under RM150K) but I am concerned about the high fuel consumption (FC). I never thought that there was a problem with FC for Mazda cars since Mazda have been promoting their Skyactiv technology in which one of the plus points is the good fuel economy of their cars with this particular technology.

It only occurred to me that Mazda cars could have this high FC problem when I visited the Mazda 3 Facebook page and saw a comment from this person, Ed War, that his new Mazda 3 was having a high FC problem. The FC claim by Mazda themselves for the Mazda 3 is 5.7L/100 KM but Ed War was only able to get around 11.4L/100 KM. Not only is that a significantly higher FC but that's about twice the claimed FC by Mazda. That is certainly a significant cause of concern for prospective Mazda 3 buyers. I mean, if the FC figure was about 2L/100 KM or even 3L/100 KM higher, then it's acceptable but for it to be twice the claimed FC, that's not acceptable at all.  Anyway, if you want to read the comments by Ed War about his Mazda 3, you can visit:
https://www.facebook.com/photo.php?fbid=101...35147626&type=1

Another link is here:
https://www.facebook.com/photo.php?fbid=101...35147626&type=1

Being more interested in Mazda 6, I took a test drive on Sunday at the Mazda showroom along Old Klang Road. I don't what the showroom did to the Mazda 6, but I saw the average FC was 20.7L/100 KM after the test drive (it was just above 22L/100 KM before the test drive). This led to to have concern that not only is Mazda 3 having high FC problem but Mazda 6 has such high FC problem too.  I attach a photo I took of the reading for you to see.

I have two questions:

1. What is the FC for your Mazda 3 or Mazda 6 if you are driving a 2013 or 2014 model?

2. Is it possible to set the average FC meter so that you can see the average fuel consumption for just one trip (could be 5 KM or 10 KM)? If so, how do you set it? I had asked the salesperson but he is not aware that it can be set for just one trip.

to answer how to achieve 11.4l/100km .

because it is call AVERAGE FC on the meter..
and those driver depends on it .. . all i can says is ... 

most car average meter will reset by itself.. so when u just drove out from car park .. stuck all the way to work it will show very very bad fc... coz it calculate base on 100km average.... if u takes 2 hours to jam to office says 20km away .. u are doing like 1 hour for 10km only .. base on the computer calculation .. to reach 100km .. u will need 10 hours..

so due to stuck in jam .. stop and go .. ur FC is doing worse n worse ... it will juz MULTIPLY to 100km and show u the average u need to hit 100km ...
(REMEMBER ... even on IDLE .. your car burn fuel .. although u need maybe 0.2 L to move per km ... maybe ur idling take up another 0.2 L already)
if u are on high way .. cruising says 100km/h ... u burning 6L ... to achieve that the ecu will tell u .. u need 6L .. look you are not wasting fuel on start stop ..

It is different on your case cause u calculate by full tank refuel.. as always the COMPUTER is calculating AVERAGE Fuel Consumption only ... it will be based on TIME and Distance travel.

So far I have to say that derraville's answer is the best answer of all the replies to this thread so far.  While most others are not answering my question or even criticising my concern of high FC in Mazda 3 or Mazda 6, derraville has been most helpful with his answers.

I think many didn't get my point. I am not expecting Mazda 3 or Mazda 6 to get the best FC. Or to have FC of a segment-B or segment-C car. My concern is that the Mazda 3 or Mazda 6 shouldn't be getting twice the claimed FC. I personally  believe that Ed War wasn't stuck in the traffic jam most of the time. If he was, I think he would have hold up his hands and admit it because no one would get a good FC during a traffic jam. Anyway, I would take derraville's average FC in his Mazda if it was offered to me because I think the FC of his Mazda is acceptable. I assume that derraville is driving a Mazda 3.

summary/average: they go between 11-13km/l and chances of heavy traffic jams in the US would be lesser compared to us.

expect 8-10 km/L

heck, didn't a mazda 3 posted his FC? considering a 6 is much heavier, further reduce maybe 2-3 km/l to be around 10 km/l maybe?
10 km/l is about 10l/100km, half of what was shown on the meter i guess

The reason why everyone else criticized on this thread, is that when you're buying a heavy D segment car, FC should be the least of your concern considering you're paying a huge premium for the car already.
If you're really that concerned, and the Mazda 6 seems to be in fact not a great performer in FC, consider another car then. (like the turbo charged ones that are in smaller cc that could probably be more frugal in FC)

=edit=
corrected previous mistake on mazda3