99magna

Hello,

I have had a 2009 Rx 350 for about 3 years now ( it had about 32.000 miles ). Up until recently, my cruising range usually display 367 miles at each fill up. A couple week ago, i filled it up to 327 miles and 4 days ago, i filled up to 303 miles. I also noticed one time on the fuel gauge it shown at 1/2 tank full, but Cruising Range only shown 127 miles. Is there a problem ?. I took it to the Lexus dealer for the problem described above, but 3 days later Lexus dealership called me to come take my Rx back and told me they can not find anything wrong with it, they also said it depends on how you drive and it varies . I may be wrong but i think they BS me because they can not find the problem to fix. What do you guys think ?. Any help or advice are greatly appreciated. Thank you in advance.

Rainbird

Are you using premium fuel? Are you driving mostly highway or city? It is a fact the vehicle's computer will adjust this mileage output based on how you drive and what fuel is used.

99magna

Yes, i am using premium fuel 93 octane ever since i bought it new. my wife drives the Rx 350 everyday taking my kid to school and back in the city driving condition. She drives it very gently and i have never seen she drives it hard.

RX330inFL

I would start keeping an accurate track of your gas mileage based on the number of miles driven divided by the fuel used. Will give you an idea of what you are getting for a true MPG and the accuracy of the trip meter.

https://www.clublexus.com/forums/rx-...-manually.html

joedaddy1

iTrader: (1)

range doesn't mean much.. need to check the MPG.. or gallons being pumped in..

stevesxm

the " range " figure is a estimate the computer makes based on manifold vacuum, and throttle position versus fuel level.

obviously for a given volume of fuel you are going to go a lot further at 1 % throttle than you are with your foot buried in the floor mat and the tires on fire. its there so that you can adjust your driving style to not run out of gas before you get where you need to , if necessary... and it probably is accurate +/- 20 % at best...

it falls squarely in the " bells and whistles" catagory

DavidTB

When I fill up my rx after mostly in town driving my cruising range is in the 267 mile range. If I' ve been driving more highway it'll be +300 miles. I figured the range is you gallons of gas times your last ave. Mpg on the computer.

Rainbird

I think you are correct. I drive mostly highway speeds and I also do 98% of the driving. I checked the cruising range and it was 395 miles after filling up this morning.

RockfordRX

I agree, it depends on your average from the last tank. When I drive in the city for a week, then fill up, the computer will give me estimate of 303 miles. When I take a 250-300 mile trip on a highway, then fill up - the computer gives me much longer range - up to 395 miles. Your complaint seems to be pretty consistent with the "normal" fuel usage we're al experiencing.

I think the Lexus dealer is correct - there is nothing wrong with the car. At 32,000 miles you're just barely getting it broken in.

stevesxm

of course it is... but what do you think that info is derived from and more to the point, what does your range and how you drove on your last " tank" have to do with how the car is driven now ?

driven agressively in town vs miniscule throtlle position on the interstate at 53 mph will result in , roughly a 30 % reduction in range or more.

its meaningless information. and, i suggest not even remotely accurate enough to rely on in any respect. think about it... if you think you are low on fuel and worried about getting where you are going, you intuitively drive slowly and with small throttle opening... you don't look over there and say
gee " it says i can go 203 miles... ill just drive 100 mph and run out of gas the instant i get there"

its the same thinking that gives you electrically heated glove compartment *****... meaningless bells and whistles that add complexity , drive up the cost and add no actual benefit.

i would have been MUCH happier if they had spent the extra 20 cents and put a brake light switch in my car that doesn't make my dash light up like a vegas slot machine...

jfelbab

It's not meaningless at all, IMO. For me, it yields a reasonably accurate estimate of how far I can go before refueling. Typically it is in the 330-345 mile range when I refuel but this is not a static number that is fixed. I find the estimates fairly close to actual and it is constantly being updated as you drive to be more precise. It is much more accurate than looking at a gas gauge and trying to determine whether you have enough fuel to make the next major city.

For me, the estimates are fairly accurate. It sounds like your system may not be.

takeshi74

So what changed?

Has she been doing this all 3 years that you've owned the RX? Didn't school start recently? It's not just a matter of "driving hard" versus "driving gently" but city versus highway as well. Is your RX doing more city driving now that school is back in session?

Completely subjective. It should be obvious that no mass produced product will perfectly fit any one person's notion of meaningful and of benefit on all points. One person's meaningless bell/whistle is another person's useful feature. If you want barebones utilitarian features then you probably bought into the wrong market segment.

I'm not sure that straw man argument thinking is really any better.

It's a very YMMV thing. The computer obviously doesn't have a crystal ball and while it does update constantly it can't predict how your future driving will be and there is certainly room for discrepancies. I think rather than state that it is "meaningless" the person above should have said that you need to consider it's limitations if you're replying on it.

You probably find it less meaningless because your driving style is more consistent. I suspect it's driving style more than the system.

99magna

The changed is approximately 60 miles less than what is used to be indicated on the cruising range. My wife driving habit is always the same, nothing changed. i am kinda puzzled by this.

stevesxm

well its the opportunity to do a good test AND get your answer quite specifically. 60 miles is about 16 % of your range. so that suggests that your actual fuel milage should be 16 % lower. thats a meaningful and quantifiable number... about 3 MPG give or take...

so do a real world calculation. fill the tank, drive a couple hundred miles and refill the tank and do the math. if your milage is bad then the car is running rich which is no good at all.. the greater the number of times you run the test, the more accurate the data will be.

also... you might want to be aware that winter milage is often worse than summer milage because the cold start system richens the mixture for longer because the car takes a bit longer to warm up and the formulation of winter fuel is traditionally a lesse fficient blend... but having said that, 16 % , if accurate, is way outside those likely effects. not to mention that its not winter yet...

the water temp gage isn't reading lower than normal is it by any chance ?

Jumper73

Also keep in mind that your mpg will gradually decrease longer you have the car, due to many different factors other than driving style. As it age, it's performance will decrease just like our bodies do or anything else in life. It'll never stay constant forever.

Tuning the car to optimal level will keep it more constant, but bottom line is all cars will eventually have less mpg than when you had the car new or newer.

For example, I currently have '02 Altima bought new in 2001. At that time, it was getting calculated 27 mpg city/hwy combined. Although meticulously maintained throughout (I self maintain all my cars except for MAJOR work, which I entrust to my mechanic I've dealt with for 15+ years) mpg has gradually decreased to a point where it now gets about 23 mpg combined. No amount of tuning/cleaning will bring this altima back up to 27 mpg unless some major work is done to the car and parts are swapped.

If it somehow changed drastically over 1 fill up, then yes it's a good indication something is off.

Some of the simple things you could check would be air filter, proper tire pressure, brakes. More extensive would be fuel injector (possibly could use a cleaning if never done), engine tune (spark plugs, line), temp sensor.

Good reference site: http://www.fueleconomy.gov/feg/factors.shtml

GL in your investigation.