Average Mileage Fuel Efficiency Decreasing?

[Vacation_On]

Hi: I have a Rx450h, 2010 model. approaching 6 years with it. I love it and drives great. However I'm noticing fuel efficiency would always be around 25-26 MPG but lately its more around 22-23. I've tried to drive paying attention to have a "softer" gas pedal. I drive mostly around town, lots of red lights, stopping and going. Which is what it has always been since the beginning. Anyone experience reduction in MPG? or perhaps does anyone have suggestions what things to check? I take the car to the dealership for service as scheduled, and tire pressure is always good. I appreciate any thoughts. TIA

[1990LS400]

Are you manually computing fuel mileage over over a long period of time? I've tracked all fuel used in our vehicles since the 1970's and none have routinely achieved very close to the EPA estimates. Our Prius v hybrid wagon is all over the map on fuel economy varying from about 35 mpg to 42 mpg even though it is rated 44 mpg city, 42 mpg highway and 40 mpg combined - during this summer it is in the 38 to 40 mpg range.

Here is a link to reported fuel economy for the 2010 RX460h on the EPA website: https://www.fueleconomy.gov/!Removed!/Find.do?action=sbs&id=26473 Not many owners reported but some are getting similar fuel economy as you are getting.

[VBdenny]

Not sure if you can find it in Texas but when I was last in New York State I found many stations (including Sunoco) that sell NON-ALCOHOL Premium gasoline. I gained 3 MPG with 2 different vehicles using this fuel. I certainly wish they would sell it everywhere as the alcohol really diminishes your fuel economy.

My IS250 has ranged from 19.7 - 27.1 in various driving situations. Of course I never really considered the fuel economy when I purchased the car.

[Steveski]

The main item you can do with the new engines today it to clean the fuel injectors. You should add a cleaner yearly to a gas tank to do this. I have found that "Seafoam" works for me and others.

You should also check your air filter. Keep it clean as it can mess up your fuel ratios if it get pluged up. I use a K&N filter with increased capacity and can clean it when it gets dirt. You plugs will last 100k miles. Aslo keep your tires up to pressure noted in your manual and should be noted on a door tag. Hope this Helps!

[VBdenny]

The K&N filter is an excellent suggestion. I have them in all my vehicles. Not sure the slow and easy method saves much gas. I usually floor it off a light and still get about the same. With gasoline dropping into the $1.80's a gallon, who really cares? I'm burning as much as I can while it's cheap.

[Sasha L]

Leased a brand new 2013 F Sport and noticed the same thing about fuel consumption. First year the best city mpg was around 16,5.

The following two years it steadily declined to just around 15 mpg right now.

Driving habits remain similar throughout the time period as is the type of fuel 87 and the brand Chevron.

[VBdenny]

87 in that? Suppose to take 93. That is why fuel economy is at 15 because computer degrades performance to not damage engine. You should get at least 19 even with flatfooting

[1990LS400]

87 in that? Suppose to take 93. That is why fuel economy is at 15 because computer degrades performance to not damage engine. You should get at least 19 even with flatfooting

The same V6 engine used the 2013 RX350 F-sport, regular RX350, ES350, etc. is used in a number of Toyota brand vehicles including the Camry, Sienna and Highlander. Regular gas is specified for the Toyota vehicles for an output of 266 HP. Premium gas is specified for the Lexus vehicles for an output of 270.

The 2013 RX350 F-sport with the 8-speed transmission is EPA rated at 18 mpg city, 26 mpg highway. My 2014 Sienna with the same engine but the regular 6-speed transmission instead of the 8-speed is rated at 18 mpg city, 25 mpg highway as is the regular 2013 RX350 with the 6-speed transmission.

It's up to the individual whether or not to pay more for premium gas to get four more horsepower. I tried using premium gas in our Camry V6 a few times and couldn't tell a difference in performance.

15 to 16 mpg sounds about right for an F-Sport if driven a little hard in city driving but it should get at least 22 mpg on the highway.

[Vacation_On]

I still take the car for service at the dealership and they do the comprehensive maintenance as recommended by mileage. So I'm assuming filters, injectors etc are reviewed by the techs. Thanks for your comments!

[Sasha L]

All I was trying to point out was, a brand new vehicle in less then two years, mpg rating fell from 16,5 to 15.

As mentioned before, the driving habits remained the same. Normal driving style, non aggressive. Tire pressure up to specs. The gas type and even the brand during the time period was same as well.

Filled up with premium gas a couple of times as well with no major improvement, saw roughly same mpg rating.

Just got a 2015 RX front wheel drive. Will see how it's consumption works out. But the EPA is slightly lower then that of a 2013 F-sport which is an all wheel drive.

[1990LS400]

All I was trying to point out was, a brand new vehicle in less then two years, mpg rating fell from 16,5 to 15.

As mentioned before, the driving habits remained the same. Normal driving style, non aggressive. Tire pressure up to specs. The gas type and even the brand during the time period was same as well.

Filled up with premium gas a couple of times as well with no major improvement, saw roughly same mpg rating.

Just got a 2015 RX front wheel drive. Will see how it's consumption works out. But the EPA is slightly lower then that of a 2013 F-sport which is an all wheel drive.

Both 16.5 and 15 mpg seem pretty bad for a gently driven RX350 F-Sport if that is your overall average numerous fill-ups and represents a typical mix of city and highway driving - unless you usually drive in stop-and-go traffic or on surface streets and rarely drive at highway speeds.

My FWD Sienna with the same engine averages about 20 mpg in combined city/highway driving and a little over 23 mpg on long highway trips at a constant 70 mph. The RX350 and the Sienna have very similar (heavy!) weights although the RX350 has a little better coefficient of drag factor at .27 vs. .309 of the Sienna. The V8 2000 LS400 I sold last year weighed 700 pounds less than my Sienna and got far better gas mileage - particularly at highway speeds.

I wouldn't expect the gas mileage of a FWD 2015 RX350 to be much different than an AWD 2013 RX350 F-Sport.

[Sasha L]

It was a combination of both the highway and city with slightly more then half of it ramped up in the city.

Pretty much exact same setting, the route as well as speeds at which traveled.

Almost a third of city mileage came from streets, if driven at certain speeds(25-30 mph) a stream line affect, meaning no need to stop at traffic lights, would be achieved.

I guess what I'm trying to say is that with identical settings the drop in gas consumption for a new vehicle should not be that great. And to me a 1,5 mile per gallon drop in such a short period of time is somewhat great. One could only wonder what that drop could be when the vehicle becomes a little more older.

Not to mention it never came close to EPA listed on the sticker.