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We have a new gas station in our area that has a gas pump for "clean gas" which is ethanol free.
The clean gas only comes as 91 octane and is $0.30 per gallon more expensive than their 10 % ethanol 91 octane gas.
I normally use COSTCO's 92 octane E10 gas. I tried four tankfulls of the clean gas and got 20.81 mpg with it.
With the previous 4 tanks of E10 92 octane gas I got 19.24 mpg.
I ungerstood that ethanol was bad for engines in that it caused corrosion in the fuel system and was bad for
rubber seals for starters. But that was for older cars, and that later model engines were built for the ethanol
gas. We have a 2011 RX350 which I assume is in the later model category.
For an additional 1.6 mpg I don't think it is worth the extra cost. Any comments are welcome.
Anyway, I thought that I would share my experiment with you all.
George
Got a 2012 Rx 350 AWD with 90k miles. Getting very poor MPG. On a 100 mile freeway trip today at 80 MPH, I was only able to get 20 MPG. What's going on? Should I be using Techron or something to clean the fuel system or something? I dont drive with a heavy foot at all.
For reference I have a Highlander where I get 24 MPG highway, a Tundra where I get 17 MPG highway, and a GS 350 where I get 25-26 MPG highway.
Got a 2012 Rx 350 AWD with 90k miles. Getting very poor MPG. On a 100 mile freeway trip today at 80 MPH, I was only able to get 20 MPG. What's going on? Should I be using Techron or something to clean the fuel system or something? I dont drive with a heavy foot at all.
For reference I have a Highlander where I get 24 MPG highway, a Tundra where I get 17 MPG highway, and a GS 350 where I get 25-26 MPG highway.
First, make sure your tires are properly inflated. And then try a different brand of gas (not premium, but a regular from a different gas station)
I get similar MPG to yours, I tried driving slower, closer to 60 MPH and my MPG improved dramatically, I get above 25 MPG. But when I drive my usual 70-75 MPH, I still get about 23MPG
Got a 2012 Rx 350 AWD with 90k miles. Getting very poor MPG. On a 100 mile freeway trip today at 80 MPH, I was only able to get 20 MPG. What's going on? Should I be using Techron or something to clean the fuel system or something? I dont drive with a heavy foot at all.
For reference I have a Highlander where I get 24 MPG highway, a Tundra where I get 17 MPG highway, and a GS 350 where I get 25-26 MPG highway.
I have a 2013 RX 350 FWD with 90K, and I get about 23 mpg on the interstate at about 75 mph. Not sure about how much effect the AWD has, but I would think it would be at least one mpg less. The extra five mph would have a little effect also. The other factor could be the gas supplier, which I have found can vary a good two miles per gallon. Speed, temperature, tire inflation, elevation changes and ethanol percentage will all affect mileage. BTW, I have found that the only accurate mileage readout is from the "after fueling mileage" mode.
Got a 2012 Rx 350 AWD with 90k miles. Getting very poor MPG. On a 100 mile freeway trip today at 80 MPH, I was only able to get 20 MPG. What's going on? Should I be using Techron or something to clean the fuel system or something? I dont drive with a heavy foot at all.
20 actually sounds about right. I regularly take a long drive to pick up/drop my daughter at college. The first few hours are 55-60 speed limit (so 65-70) and it hovers around 24mpg. When I get on a 70mph highway (traveling 75-77), my tank average immediately starts dropping. It ends at about 22.5-23, so I'm getting about 21.
Aero drag increases as the square of the speed so 20mpg at 80 (14% more drag than at 75) sounds just about right. It's rated at 24 (not great to start with), and that's tested at 65-70mph.
22 mpg to 24 mpg is about the best my wife's 2015 RX350 FWD can do. That is steady cruise-control highway driving around 70 to 72 mph. Speed up to 80 or 85 mph and it drops by at least 2 to 3 mpg.
2010 with 129k miles and with a lot of surface street driving and an occasional hwy drive or two we have been getting a consistent 19mpg and never under 300 miles to the tank. a fillup seems to take 16 to 16.5 gallons.
I bought my used 2013 rx350 awd with 79K miles, since then have put 6k miles on it I drive M-F from NJ to NY and then from NY back to NJ. At first I was getting about 14-16mpg after refuel not the average mileage on the computer. So I put in a bottle of fuel injector cleaner and that improved the mileage to about 17mpg and then I changed the engine air filter which I have a picture of below: The before and after. pictures... and now I average about 18.5mpg to as high as 21mpg driving between NY and NJ, you would think its alot of highway miles but its pretty much stop and go traffic during morning rush hour traffic and after work rush hour traffic speeds upwards of 30miles/hr before stopping again.
Extra bonus Cabin Air Filter before and after:
Cabin Air Filter... Yikes! previous owner... New Engine Air Filter Old Engine Air Filter had lots of particles between the folds, some of the people who get low mileage maybe its due to the engine air filter looking like this...
Last edited by darkstorm8; 11-12-19 at 10:24 AM.
Reason: adding more comments
It looks like you significantly improved you MPG with a just a few simple maintenance procedures. I've been using a Top-Tier gasoline in my 2015 Rx350 AWD for the past 9K miles. I tried a bottle of Techron fuel injection cleaner and found absolutely no change in MPG. It looks like the detergents in the Top-Tier gasoline are doing the job of keeping the injectors clean. I average about 22.4 MPG in the winter months and 24.0 MPG in the summer months with mostly rural driving in South Jersey.
I bought my used 2013 rx350 awd with 79K miles, since then have put 6k miles on it I drive M-F from NJ to NY and then from NY back to NJ. At first I was getting about 14-16mpg after refuel not the average mileage on the computer. So I put in a bottle of fuel injector cleaner and that improved the mileage to about 17mpg and then I changed the engine air filter which I have a picture of below: The before and after. pictures... and now I average about 18.5mpg to as high as 21mpg driving between NY and NJ, you would think its alot of highway miles but its pretty much stop and go traffic during morning rush hour traffic and after work rush hour traffic speeds upwards of 30miles/hr before stopping again.
Extra bonus Cabin Air Filter before and after:
Cabin Air Filter... Yikes! previous owner... New Engine Air Filter Old Engine Air Filter had lots of particles between the folds, some of the people who get low mileage maybe its due to the engine air filter looking like this...
Not being a mechanic or even a car buff....I am wondering how the cabin air filter affects fuel mileage. Thanks.
A heavily-clogged cabin air filter will require the A/C compressor to work harder, which could indeed reduce the vehicle's MPG performance somewhat. By exactly how much would be difficult to measure and may vary from vehicle to vehicle.
To verify, I did skim through the fuel mileage thread, and payed attention to the most recent posts. The first dozen pages were mainly brand new vehicles that hadn’t been broken in yet. However in the most recent posts, I noticed Most people were complaining about 22-23mpg which to me is perfectly normal. And I didnt Find many suggestions that I havent Already done yet. My fuel mileage on the highway at 75mph cruise control in west Texas (flat) with a tail wind, I’m averaging 17.5 to 18.4. With a headwind, it’s dipping closer to the 14’s. It’s 2010 350 AWD with 150k miles. New filters, premium 91 100% ethanol free fuel, 2 new front struts, rear shocks, front wheel bearings, pads and rotors on all 4 corners, 4 wheel alignment, lof service, 4 new tires, 4 new sway bar links, throttle body cleaning, and 4 new cv axles all done within the last 2 months. Still no increase in fuel mileage. Took the car on a 4 hour 280 mile one way trip to Eskridge Lexus in Oklahoma City with the fuel mileage concern and they ‘found no abnormalities at this time’. I also own a 2004 RX330 with 92k miles that averages 24mpg and my 2008 RX350 with 205K miles averages 26mpg Highway. The 2010 runs smooth, no codes stored in the computers, good power, quiet running. But absolutely crappy fuel mileage. What else could my issue be??
To verify, I did skim through the fuel mileage thread, and payed attention to the most recent posts. The first dozen pages were mainly brand new vehicles that hadn’t been broken in yet. However in the most recent posts, I noticed Most people were complaining about 22-23mpg which to me is perfectly normal. And I didnt Find many suggestions that I havent Already done yet. My fuel mileage on the highway at 75mph cruise control in west Texas (flat) with a tail wind, I’m averaging 17.5 to 18.4. With a headwind, it’s dipping closer to the 14’s. It’s 2010 350 AWD with 150k miles. New filters, premium 91 100% ethanol free fuel, 2 new front struts, rear shocks, front wheel bearings, pads and rotors on all 4 corners, 4 wheel alignment, lof service, 4 new tires, 4 new sway bar links, throttle body cleaning, and 4 new cv axles all done within the last 2 months. Still no increase in fuel mileage. Took the car on a 4 hour 280 mile one way trip to Eskridge Lexus in Oklahoma City with the fuel mileage concern and they ‘found no abnormalities at this time’. I also own a 2004 RX330 with 92k miles that averages 24mpg and my 2008 RX350 with 205K miles averages 26mpg Highway. The 2010 runs smooth, no codes stored in the computers, good power, quiet running. But absolutely crappy fuel mileage. What else could my issue be??
Not sure what your issue can be. AWD might reduce mileage one MPG or so, tire pressure could be another one maybe, and specific gas source (contaminated?) could be another. Not sure what the 2010 models should get either. Engine, or aerodynamic drag could be another problem, but you are correct that you should likely be getting better mileage.
In my case, I have a 2013 FWD RX350, with 80K miles on it. On interstate driving, both directions, all weather conditions, I average 22-23 MPG (after fueling), on 400 mile trips averaging 75 MPH. I use regular gas with up to 10% ethanol, and tire pressure about 34 psi in the larger wheel option. From what I can see on this post that is a decent average, with some higher and some lower.
09-16-19, 12:37 PM
Clean gas experiment
