99ls40, 49mpg Current Fuel Consumption Reading

afaleti · August 7, 2004

I just noticed that the Mode that displays the current fuel consumption in my 99 LS400 is faulty, it shows Readings as High as 5mpg down to 49mpg ( I wish).

Does anyone have the slightest clue as to what needs to be replaced and what it might cost?

All the other modes work perfectly.

Range

Elapsed Time

Average gas Consumption

etc .....

jbarhorst2 · August 7, 2004

Why are you so sure that it is wrong??

As you accelerate and decelerate your consumption does go through large swings.

Accelerating away from a stop light - high fuel usage - low MPG.

Coasting down the road - low fuel usage - high MPG.

afaleti · August 7, 2004

Why are you so sure that it is wrong??
As you accelerate and decelerate your consumption does go through large swings.

Accelerating away from a stop light - high fuel usage - low MPG.

Coasting down the road - low fuel usage - high MPG.

Not when i am cruising at same speed ?

vevro · August 7, 2004

There's nothing wrong with your computer readings. My car reaches 99.99 mpg at cruising speeds down a hill. :cheers:

99lsguy · August 7, 2004

Yes,

You'll get instant readings that change constantly over terrain........but on a long, consistent stretch is should be steady....

jbarhorst2 · August 7, 2004

Right. Even when you are cruising at the same speed. As you go up and down hills (even very slight ones that you cannot see) you will see your mileage change based on how hard the car is working to keep you at the same speed.

Tom

SW03ES · August 8, 2004

Agreed, sounds like the readout is working properly.

You've got to remember thats current consumption, not average. Its the economy the car is getting at that particular moment in time. In order to average say 20MPG you'd have to get higher mileage some times.

90LS400Lexus · August 8, 2004

True- my old 1995 Chrysler Concorde had the MPG computer. When I could go down the grade on the highway- at speeds over 60 MPH, when I was not accelerating- it would go to 99 MPG- then decrease as I accelerated. It also had a button that you could click "average MPG" that would show you the average. It also had the digital compass, outdoor temperature. I actually miss that car, but the money I got for that car was what I bought the LS400 with. Went from a 1995 Chrysler with 93K miles, to a 1990 Lexus with 224K. :rolleyes: The Chrysler was developing a knock though I think. Transmission was still quirky- even after a $900 rebuild. Thought it was time to sell. What a ride that car had- it was like riding on air, but handling was still supurb- excellent braking too.