Fuel Consumption Question For Ls400?

lexusdriver · September 23, 2009

Hi,

I'm a new owner (1 week) of '98 LS400. On a drive, mostly motorway at 80mph, with some traffic jams and small distance of urban driving I'm getting 24mpg (UK). I had thought thas I might get better than this. Keeping below 70 mph definitely helps but where's the fun!?

lexusdriver · September 23, 2009

Has anyone got any further information on an LPG conversion on their LS400? I've a 'R' reg '98 model and wondering whether a conversion is worthwhile. I on;y drive around 8.000 mile/year though!!?

Crazy Pete · September 25, 2009

Hi,
I am looking at buying a '96 LS400SE, but the only thing that is stopping me is the possible fuel consumption. Obviously 4 litres is a big engine, but what sort of fuel consumption are people genuinely getting out of theirs?

Thanks in advance.

I have a 1997 LS400 and have done about 4000 mls since I had it. I fill the tank from empty, costs about £70-£77. I zero the clock every time, (old habit from company car days) I get 30 mpg on a run and I get between 23.5 lowest to 26.3 highest around town. I usually drive it like a Lexus but I do like to sort out a few wanabees from time to time lol. Every time I give some1 a lift they love it, makes u feel great.

1998Ls400 · May 17, 2012

I recently own a ls400 1998 model with 200k and in town i got around 17 mpg (uk gallons) driveing gentle...i readed that normal the comsumption its arount 20 mpg in town! It can be a problem? Thanks

Titch LS · September 7, 2012

Had mine converted about 9 months ago. Best thing I ever did. Averaging 26 miles per gallon with LPG on my daily commute to work on mainly A-roads. (and I don't crawl along). Absolutely fabulous cars. Wish I'd bought one years ago. Really enjoy driving it every time I get in it.

malcolmdc · February 10, 2015

Hi Guys, I recently bought the 1991 LS400 with only 22000 miles on it - a "new" engine by Lexus standards - and after 3 tankfuls ave mpg in all this cold weather stop-start is 21.5. The first 2 tanks were on an air filter which I (later) found to be like a chimney-sweeps brush, so having changed that, and with warmer weather we should see an improvement. Legacy of a company car got me in the habit of brimming the tank, and recording mileages/fuel, sad bugger!

Malc · February 10, 2015

wow, so tell us more about your rare Mk1 please ............ and some photos too

Thanks

Malc

Colin M · February 10, 2015

Yes, let's see some photos please.

Not many Ls400s around with such low mileage. 21.5 mpg sounds good to me at this time of the year.

alien1974 · February 10, 2015

I recently own a ls400 1998 model with 200k and in town i got around 17 mpg (uk gallons) driveing gentle...i readed that normal the comsumption its arount 20 mpg in town! It can be a problem? Thanks

i have the same issue too mines done 97k though

alien1974 · February 19, 2015

found this on a lambda website quite interesting

ECU's are progressively becoming able to accurately identify a failing lambda sensor, but for older engine management systems, this is not the case. Fault codes do exist for lambda failure but most older ECU's only detect an absence of signal, for example if you had cut the sensor wires, or average 'too rich' and average 'too lean' mixtures over a long period of time. These fault codes do not always work but the increasing number of Lambda-code related MOT failures we encounter would support their usefulness. It still applies that the absence of a lambda-related fault code cannot be taken as a guarantee the Lambda is functioning correctly. This is especially true of some ECU systems with sophisticated LOS strategies, such as Toyota or Lexus, which will cope with a failing sensor but fuel consumption will be markedly up as a result of more fuel being used to maintain driveability