im about to pick up a 2000 LS400 with 83k miles. i took it out for a test drive and noticed the cluster's calculated avg fuel consumption is 11.5mpg; which is EXTREMELY LOW since the car is rated to get about 20 and some users have gotten up to 29 mpg on stock setup.

my question is... should i ignore the calculated average? i was told by a friend that the computer bases its calculation base on the previous drive and reseting the ecu can reset the calculations. the car is currently at a dealer so i doubt theyll let me toy with that.

thanx for the help in advance

 

11mpg is about what it gets before the engine heats up to temp.
So maybe its been just moved about the parking a lot.

OR could be something wrong with it. Get a written guarantee before you buy.

 

ur looking at the "Tank Average" right...

 

the car was started 5 min before we drove it. drove it for about 10 min approximate distance of 1.5miles to 2. the temp needle was at 1/4 from the bottom. so it it could be due to the engine still being cold.

we did get it check from our own trusted family mechanic. he said theres nothing wrong with it besides a slight leak with the rack and pinion, and the timing belt needs to be replaced soon which iam well aware or prior to taking the car out for a spin.

how do i go about getting a written guarantee and what exactly is it? this will be the first vehicle purchase that i am really involved in since this will be the 1st car that will be bought for me, and the first car being bought used. thanx again for the help


PUREDRIFTER, i did not notice if it said tank average or not, even it was tank average 11.5mpg is still crappy. i was so stunned when i saw 11.5mpg that i didnt notice if it said tank average or not. hahaha thanx for your input as well

 

my point was that it probably WASNT the tank average, but rather the "current" or "instantaneous" average.

 

dont go by those things unless you reset it regularly. they calculate mpg by distance traveled and time with engine running. so if one sits in traffic a lot, the average will drop dramatically because you're not driving anywhere but the engine is running and using fuel. so reset the computer, and go for a short drive. look at the mileage and see what it says. most likely, it will be right where it should be.

 

thanx, everyone is giving me different answers i dunno as to who to believe haha

 

stop worrying. LOL. posting this everywhere on the interwebz LOL. cb7tuner ftw!!

 

This is correct. If the engine is operating and sitting in traffic, or in a parking lot for exmaple, the MPG drops significantly. Which is always the case at the dealer as they start the car to show the customer the different features and whistles. Those meters aren't very accurate for that very reason, that is why I usually measure gas millage by miles traveled over the span of the tank (or half tank).