2007 Mazda3 GT – 4,385 km fuel economy test

2007 Mazda3 GT with 2.3-litre DOHC engine and 'archaic' 5-speed automatic delivered an impressive over 3,485 kilometre trip

2007 Mazda3 GT with 2.3-litre DOHC engine and ‘archaic’ 5-speed automatic delivered an impressive 8.0 L/100 km average over a recent 4.385 kilometre road trip

Everybody grumps about the cost of gas. But when I ask the complainers ‘exactly how many litres per 100 kilometres or miles per gallon does your vehicle get?’, a dumb look and shrug of the shoulders is generally the response I get.

OK, so most people know that the cost of filling up is on a painful, steady increase.  But how much is that increase actually costing you?  The only way to find out is to precisely measure a vehicle’s fuel economy.  (I never rely on a vehicle’s onboard computer readout.  They’re generally inaccurate.)  And you measure fuel economy by recording the kilometres driven and litres of fuel used.

Ingrid and I recently returned from a 2-week, 4385 kilometre road trip to Vancouver Island, the gorgeous Olympic Peninsula in Washington State, and a wedding in southern B.C.  Our 2007 Mazda 3GT, now eight model years old, performed impressively, not only returning some very good fuel economy numbers, but it was also a fun-to- drive sport compact sedan when the pavement got twisty.

Our Mazda3 isn’t new, but if you’re not familiar with this superb front-wheel-drive compact sport sedan, here’s an overview.

2007 Mazda3 GT’s major specs.:

  • Current mileage:  49,878 kilometres
  • Engine:  156 horsepower @ 6500 rpm, 2.3-litre DOHC inline 4-cylinder, fuel injected
  • Transmission:  5-speed automatic
  • Tires:  OEM 205/50R17 Goodyear RS-A


I watched a recent episode of Fifth Gear, an enthusiast-oriented TV series produced in the U.K.  They wanted to measure the horsepower increases, if any,  (as measured on a dynometer) on an older Volkswagen Scirocco VR6.  They discovered the single cheapest and easiest way to increase power was to add one container of off-the-shelf fuel injector cleaner.  This action resulted in an impressive 3 horsepower gain, if I recall correctly.

So who doesn’t want to bump up the horsepower on an aging car?  I imagine a chemical cleaning of the fuel injection system increases the engine’s efficiency, and an increase in engine efficiency ought to result in better fuel economy.

I picked up a bottle of Lucas fuel injector cleaner at Canadian Tire.  There are many brands to choose from.  The Lucas injector cleaner cost about $5.00 and dumped it in the first tank of gas of the trip.

2007 Mazda3 GT fuel economy (June 12-July 4, 2014)

  • Trip length:  4,385 kilometres
  • Total fuel used:  351.4 litres (regular unleaded)
  • Total fuel cost:  $453.34 Cdn
  • Average fuel economy: 8.01 L/100 km (35.2 miles per Imperial gallon, 29.3 miles per U.S. gallon)
  • Best fuel economy (Calgary, AB to Kamloops, BC):  6.49 L/100 km (43.5 miles per Imperial gallon, 36.2 miles per U.S. gallon)
  • Worst fuel economy (Red Deer, AB to Calgary, AB):  9.93 L/100 km (28.4 miles per Imperial gallon, 23.6 miles per U.S. gallon)


Best fuel economy of 6.49 L/100 km was achieved in highway driving between Calgary and Kamloops.  That drive runs through Banff National Park, most of which has an 80 km/h speed limit.  We kept up with the flow of traffic, which was running at about 90 km/h/

Worst fuel economy included a few days of city driving in Calgary.


Overall, we’re really happy with how the Mazda3 GT performed, even with what is now considered to be a somewhat ‘archaic’ 5-speed automatic transmission.  (The current crop of compact sedans with 4-cylinder engines are fitted with 6-speed automatics or the even more efficient CVT continuously-variable transmissions.)  These fuel economy numbers are still very competitive with the latest offerings in the compact car segment.

1 Comment

  1. Otilio Guerra says:

    Funny site. I was searching for 2007 Mazda 3 GT fuel tank size. I saw the worst fuel economy to my surprise Calgary. I’ve notice the same thing. I can drive from Calgary to Moose Jaw non stop or Calgary to Kamloops (100 km of fuel remaining). City driving in Calgary makes me paranoid that at times I think the car is leaking fuel.

    Rolled out from factory back in December 2006 and still looks better than some of the new cars. Phantom Blue.

Leave a Comment