Hi everyone, I have noticed my IS250 auto seems very reluctant to accelerate when cold or even change up to 6th.I imagine this is programed to behave in this way so as not to thrash a cold engine and cause possible damage. When up to temperature it goes really well.

By the way I am getting an average of 32mpg totally on urban driving with climate on and seat heating ect, very pleased. Recent trip to France over 1000 miles returned 38mpg, even more pleased.

Yes same here when cold, foot to the floor and it won't go like you want it - it's a feature to get the engine warmed up as soon as possible ( emmissions ).

That's deliberate and perfectly normal with any automatic, so don't worry.


I'm really impressed with the economy too. My 250SE has been averaging 35mpg on my drive to and from work recently (80% motorway, 20% urban) - and that's despite some really cold starts.

Well personally I try never to exceed 2000 rpm until any car engine is up to temperature....wouldn't anyone with an ounce of Engineering knowledge do the same?

is it just mine that seems to be averaging on 24mpg then??

If you're doing short urban runs in the current weather then I wouldn't be surprised.

Mines dropped about 3 mpg since the cold spell on the same journeys.

been like that since I got her at the beginning of november

Do you reset it on every journey ? i think thats what your supposed to do

It depends how far you drive and how you drive. I could envisage journeys that would only give 24mpg.

I drive 25 miles to work on mainly dual carriageway at a steady 70mph with no roundabouts. I also live in the sticks, so no traffic to prevent my engine warming up reasonably quickly. Finally, I rarely exceed 3000rpm.

That tends to gives me about 34-35mpg.

My IS250 (12 months old, 25000km) is driving 50% of time to work, and 50% local trips.
The work trips are appx 70% motorway, and 30% stop/start. The local trips I suppose average 15-20 minutes of urban driving.

According to my trip computer I was getting about 27mpg. I decided to check this with actual consumption, by filling the tank to the brim, resetting the trip odometer, and dividing the mileage by the fuel loaded at the next refill. ie. exact measurement, ignoring the trip computer, but relying on the mileage reported by the odometer.

Turns out I was actually only getting 21mpg. This was with lots of aggressive acceleration, which is my normal driving style. (I didn't by a 2.5L car to drive slowly ).

I tried then doing the opposite, and for one whole thank, I drove as fuel friendly as I possibly could....low acceleration, ensureing that I stopped at traffic lights with as low speed (and as little braking and lost energy) as possible etc. I managed 27mpg. So I'm really surprised at 38mpg!

Will I now drive ultra conseratively to get 25% more mileage? We'll as I said, I didn't buy a 2.5L car to plod along in

after a cold night when the engine is cold, does anyone feel/hear their IS 250's engine rattle? it seems when the engine gets really cold and when i start driving, the engine feels and sounds like its rattling as i am accelerating. the rattle goes away after a couple of minutes of driving. I am just wondering if this is normal

Re-set what?

I don't know the IS200 at all, but my IS 250 SE-L shows (by cycling through the display) :-

Overall average - i.e. the overall average for all the miles and all the petrol purchased since new.

Tank average - i.e. the average consumption since the tank was last topped up.

Instantaneous consumption - i.e. the notional consumption resulting from the way the vehicle is being driven at the moment that the display is read.

None of these readings require anything to be re-set, but the Overall Average can be re-set if you wish. I wouldn't see much point in doing this unless I made some significant change to the vehicle and wanted to compare the long term figures before and after. If I were to re-set it every time I put in petrol, I would expect it to have the effect of making the overall average and the tank average the same.

Incidentally, careful manual checks show that all the display figures (in my car) are a bit optimistic. For example, the overall average on the display is 31.3 m.p.g - the real figure is as shown below.

Can't say I've noticed any rattle from the engine when cold

is it just my car thats making this noise then? i mentioned this to my dealer they checked it out and said when starting up in cold weather it does make some noise and its normal but it didnt seem like they tried to drive it when it was cold, as that rattle style noise comes when accelerating

ask swager, I think he had the same problem, dealer fixed it by changing the oil to semisynthetic....