Mk3 Gs300 43 Mpg

Dilbert D · September 1, 2009

Hi all,

Just a note regarding MK3 GS300 fuel consumption and how to get the highest.

We travelled back from the midlands back to Washington up the A1 on Sunday and achieved 43 MPG over 100 miles.

The MPG was achieved almost by accident, I was not actually trying to get the high MPG.

I stopped for petrol on the A1 then continued on the journey, the fuel computer automatically reset as it detected that fuel had been put in, as expected.

A further 100 miles were then covered and the average was 43 MPG over the remaining 100 mile stint.

Now the way this was achieved was due to the fact that the roads were fairly quiet so I covered the whole journey up the A1 on cruise control gently edging the cruise speed back and forward using the stalk control to set a speed between 70 and 80 to suit the flow of traffic. I hardly used my feet at all, they were tucked back out of the way.

I only drove this way due to the fact that I rarely get chance to use cruise in daily commuting and I fancied a laid back drive after a heavy day before.

As I said I was not trying to get high MPG I was just just playing with cruise control, and the car was doing 75 or so most of the way with the flow of the traffic. The high MPG was a suprise side product !

The car is a 2006, 55000 on the clock, original plugs, tyre pressures 34 PSI all round, running Castrol Magnatec 5W30 A1 (A1 denotes fuel economy).

So if you want to beat the fuel duty increase then this is the way to do it (on a long journey on quiet roads !)

Anuj · September 4, 2009

excellent results mate.

wow300 · September 8, 2009

Wow thats some mpg for a 3Ltr car !

kns · September 9, 2009

Hi all,
Just a note regarding MK3 GS300 fuel consumption and how to get the highest.

We travelled back from the midlands back to Washington up the A1 on Sunday and achieved 43 MPG over 100 miles.

The MPG was achieved almost by accident, I was not actually trying to get the high MPG.

I stopped for petrol on the A1 then continued on the journey, the fuel computer automatically reset as it detected that fuel had been put in, as expected.

A further 100 miles were then covered and the average was 43 MPG over the remaining 100 mile stint.

Now the way this was achieved was due to the fact that the roads were fairly quiet so I covered the whole journey up the A1 on cruise control gently edging the cruise speed back and forward using the stalk control to set a speed between 70 and 80 to suit the flow of traffic. I hardly used my feet at all, they were tucked back out of the way.

I only drove this way due to the fact that I rarely get chance to use cruise in daily commuting and I fancied a laid back drive after a heavy day before.

As I said I was not trying to get high MPG I was just just playing with cruise control, and the car was doing 75 or so most of the way with the flow of the traffic. The high MPG was a suprise side product !

The car is a 2006, 55000 on the clock, original plugs, tyre pressures 34 PSI all round, running Castrol Magnatec 5W30 A1 (A1 denotes fuel economy).

So if you want to beat the fuel duty increase then this is the way to do it (on a long journey on quiet roads !)

Excellent result, although these average figures soon drop from my experience as soon as you are off the motorway and get caught in stop start traffic. Because these trip computers obviously calculate against the distance covered the mpg can vary quite a bit with just a relatively short distance of traffic.

My GS450h can show 60 plus mpg if the trip computer is reset and the first part of the journey is on mostly electric motor, unfortunately it soon drops to a more realistic figure.

The best overall average I have received on a complete long run is 35 mpg. My car has the Adaptive Cruise Control which tends to be a bit heavier on the fuel because of the way the car accelerates automatically. Despite being a hybrid I have never seen 40 plus mpg over a complete long run, so given how efficient the 3 litre engine would seem to be it’s a pity that Lexus GB have dropped the model.

Regards

Keith

Dilbert D · September 9, 2009

Excellent result, although these average figures soon drop from my experience as soon as you are off the motorway and get caught in stop start traffic. Because these trip computers obviously calculate against the distance covered the mpg can vary quite a bit with just a relatively short distance of traffic.

My GS450h can show 60 plus mpg if the trip computer is reset and the first part of the journey is on mostly electric motor, unfortunately it soon drops to a more realistic figure.

The best overall average I have received on a complete long run is 35 mpg. My car has the Adaptive Cruise Control which tends to be a bit heavier on the fuel because of the way the car accelerates automatically. Despite being a hybrid I have never seen 40 plus mpg over a complete long run, so given how efficient the 3 litre engine would seem to be it’s a pity that Lexus GB have dropped the model.

Regards

Keith

Yep, you are right, the figures are affected quickly as soon as you get off the motorway and get back into the stop start stuff. The journey from the petrol station to the motorway affects the figure greatly too since the average is calculated as a tank average.

Mind you a couple of days later the average figure had only dropped to around 34 after a couple of days driving around locally before I fuelled again, the figure was benefitting from the 43 mpg over the 100 miles

Now I am back to my daily commute the figure is back to the usual 26 to 27 mpg average over a tank fill.

The 43 mpg figure was a one off due to the fact that I was on the motorway at constant speed within minutes of fueling and then I stayed on cruise control for 100 or so miles. But it does show what the engine is capable of and demonstrates a driving style which could be used to keep fuel costs down on a long journey (other than buying a GS450h of course, I wish !)

marsden1002 · September 9, 2009

I know someone who has a GS450H, and returns, on average 29MPG over the tank. This, of course could be more if it wasnt driven hard at all, but, to say how fast it is, they are still some impressive fuel figures - when my IS200AUTO gets about 22mpg over the tank!

Dilbert D · June 8, 2010

Hi there,

Last year I posted some mpg figures of 43MPG in a 2006 GS300. I just though I would give an update on my attempt to beat that figure !

Well I have just come back from a weekend in Stamford (we live in the north east) after a weekend away.

Again I was using cruse control for 95% of the time trying not to touch the pedals, just easing the speed up and down with the stalk control. Over the 180 mile journey to stamford the tank average was 42MPG as I hit the Stamford turn off. The return journey was not as good as I could only get to 41MPG over the 180 miles as I reached the Washington turn off. Now this was not crawling along the road, the speed was maintained at between 65 and 75 for 90% of the time. At one point in the outward journey we reached road works with a speed limit of 50MPH which lasted for quite a few miles and at the end of the road works the MPG figure peaked at 44.0MPG and this was not a fleeting figure over a few miles this was the tank average over about 80 miles at that point. Obviously the figure dropped off again down to the final figure of 42 for the journey.

These figure are in Fiesta territory and pretty damn good for a 3 Litre, So it is possible to beat the 39.2MPG book figure for extra urban, but the secret is to let the car drive itself do not use your feet !!

The car is a MKIII with 61000 on the clock, tyre pressures all at 34 PSI, new plugs last week, Magnatec 5W30 A1 oil, air con only for a short period of time.

Call me sad but I just thought I would publish my little experiment, and yes I do also have a good blast down the road from time to time