fletcheee

I have a 2013 GS 350 AWD with the luxury package. Does anyone else get absolutely horrendous gas mileage in this car? I will admit I have a lead foot, so when I first purchased the car and drove it the way I wanted to I was getting max 11 miles a gallon, and I wasn’t even pushing it too often, just a few pulls here and there and using the paddles every once in a while to take a turn or roundabout in the right rev range. After having the car for a while now I’ve figured out the only way for me to even get 15 miles a gallon is to put it in eco mode and literally never touch the gas. I have to frequently calculate in my head wether or not it’s worth the gas money to be able to safely speed up and merge over. I’ve been spending a ridiculous amount of money on gas every month, to the point where it’s becoming financially unfeasible to continue driving this car, when literally anything else in this class would get significantly better gas mileage. I don’t even get to enjoy the car because I have to constantly worry that if I press the gas pedal a little bit I’ll end up getting worse gas mileage than a brand new Lamborghini Huracan, and this is all to get just 15 miles a gallon. I came from a 2012 Honda Accord V6 EX-L with a 3.5L V6 that made power comparable to the 2GR-FSE, while slightly less power if I’m being honest it felt just as quick. I drove the wheels off that thing, every other stop sign or red light I would just floor it for fun. I really pushed the thing to its limits constantly, and never once did I get anything below 20 miles a gallon and I averaged around 25. Also for some context more than 70% of my miles are highway miles with cruise control on. I have never once hit the EPA city rating of 19 miles a gallon. I specifically went to Lexus when I got my first service notice so that I could ask them about this and see if there’s anything they can do/check or if that’s just the expected gas mileage, I would have never payed 50 dollars to get my tires rotated otherwise. They said they “took a look” and everything looked normal. They just looked at the average mpg on the dash, saw it said 18.1 and said 18 isn’t bad and that’s about what I should expect. Thing is when I got the car with 107,000 miles on it the average mpg said it was 23.5. So if at 100,700 miles it was 23.5 and only 5000 miles later it’s now down to 18.1 it’s clearly getting much less than that, considering how quickly and exponentially it’s going down. I explained that to Lexus and the dude then told me anything over 10 is ok. I straight up laughed in his face, not to be disrespectful but I was just genuinely shocked that he would claim that It’s even remotely acceptable for a mid size sedan with a V6 to get the same gas mileage as the LFA. So I guess I’m wondering, is there anything I can do to improve the gas mileage on this car, and if not, is there a chance something could be working incorrectly and or broken causing me to get terrible gas mileage? I’m not very mechanically inclined so I apologize if that’s a stupid question, I just genuinely don’t understand how I can be getting this kind of gas mileage considering I actively try to conserve fuel now. Would a tune help? I know with certain tunes for BMW’s and Audi’s you can actually see better fuel economy even with more power. But maybe that doesn’t apply in this situation, it seems there’s only 2-3 tunes for this engine and the only one that’s even reasonably priced is RR racing’s tune, and they mention nothing about fuel economy other than “while retaining stock fuel economy” which I’ve never once gotten anyways. At the end of the day, I’m going to have to sell this vehicle if this is the gas mileage I’m always going to get, as I do a lot of driving and this car is running me broke. Thank you in advance for your help and answers!

Kingmatt24

I have a 2013 AWD and I've been getting 17-18 MPG all summer. Was actually getting better gas mileage in the winter/spring, my overall average was 18.6 a couple months ago but it's 18.2 now. But I do keep my AC on most of the time when it's hot, but never high fan speed or really cold unless it's extremely hot. I have a really heavy foot sometimes, like today for example. But most of the time I'm just cruising/driving like a turtle in city driving. I had my spark plugs changed a couple months ago but didn't notice any improvement in MPG, it's about the same. But in your case, 11 MPG with sporty driving and 15 MPG with slow driving is really odd. But I've read other people online have had really poor mileage like you, never saw any follow ups to see if it improved. Are you carrying a lot of extra weight in the trunk/putting at least 91 in your car?

Kingmatt24

And the way I see it, the GS is bad on gas anyway, especially if you have an AWD like us that only comes with a 6 speed. So I tend to drive with sense of urgency when I'm not in heavy, slow traffic to enjoy the car for what it is. I think the best I ever got was 21/22 MPG on my commutes to work on the expressway last fall, but I was driving in eco mode and never floored it or went over half throttle. But that's a boring way to drive and the fuel tank capacity isn't big and I was making frequent trips to the gas station even with 22 MPG.

GSJ350

I have a 15 base model so RWD and the 8 spd transmission and I get 24 city and 31-32 highway at 80mph. Your AWD and 6spd trans are working against you but still that's pretty bad MPG... Raise tire pressure to 37 or a tad higher check and make sure your air filter is clean along with maybe getting the alignment checked. An engine at it's basic level is just a air pump so easy in and easy out will give you best efficiency. Need to make sure your 0² sensors are reading correctly as well as making sure your catalytic converter is not getting clogged and creating a massive clog or back pressure scenario. All these things I've mentioned are small but could lead to 3-5mpg's better than your getting now. Also, get some lucas fuel system treatment and put it in your gas when filling up...I've had great luck using that stuff. Use only 0w-20 or 5w-20 oils if your using something else.

AJLex19

There are many threads on the "poor" gas mileage of the GS350. In my experience, there isn't much difference between my old RWD V8 GS430 and my current '13 GS350 AWD in terms of gas mileage. I always get around 14-15mpg city driving with my '13 GS350.

Lots of factors will affect MPG: All Wheel Drive impacts mpg (more components, more weight), Driving habits, Tires (touring tires usually better), Roads, age/mileage of the car, need of a tune up (oil change/spark plugs done?) and now that its summer, use of the air conditioning system impacts MPG.

One possible trick could be just disconnecting the battery for 20min and then have the ECU re-learn your driving habits to see if that changes anything. As fellow member @GSJ350 mentioned, check for any bad O2 sensors, maybe clean out the throttle body/MAF sensor, check to see if you have any exhaust leaks or a bad catalytic converter.

Last thing that comes to mind is any modifications to your car in terms of exhaust, intake, wheels/suspension can also affect your gas mileage.

Cwang

The RWD 6 speed GS350 is rated at 17MPG urban. It really shouldn't go much higher though, 11-15 is something is wrong territory, that's Subaru bad.

Don't go part swapping without doing an ECU reset (pull battery). Get your fuel system checked, blocked fuel filter isn't hard to change and could cause bad economy. See black smoke come out of the exhaust? Throttle body clean? Check the MAF sensor, they don't have to be dead to bugger your fuel economy. Tyres up?

Wouldn't oxygen sensors be a likely culprit? If they're telling the engine to run too rich you're burning money. They are only meant to last 100000km anyways. Not hard to change.

I wonder whether a teenager had a hold of it before you and buggered around with the MAF or something. Is the performance right? Your 0-100 (or 0-62 miles) should be around 6 seconds on level ground. If it's closer to 7, I suspect something is wrong.

703

Disconnecting battery does not reset transmission ECU. That is urban myth for the car concerned.

I had a GS460, it’s absolute worse economy was doing short 5km trips in the suburb at around 16mpg.

Now with the Gs450h, the worse is 30mpg.

Cwang

As far as I know, the transmission isn't intelligently adaptive anyways. My last commodore had a GM smart transmission that learned how you drive and remembered.

Gr8

Wow..... MPGs in teens for the most 6-speed GS350?! My average is at 24.9 mpg right now, and about 60% of my drive is on the country backroads, and 40% is on the highway on my 2016 GS350 AWD. Its not uncommon for me to go over 400 miles on a single fill. The best I have ever gotten was 31.1 mpg on all highway miles.

BTW, some might think I drive like a grand-pa or something, but anyone that rode with me can contradict that.

Pictures of proof.


Max I have ever gotten out of my GS. I could still go another few miles, but I wasn't feeling brave enough that day.



This was right after refueling while driving to and from Pittsburg PA/Germantown MD. Though it was during winter and my AC was not running as much.




Took this picture at the gas station after refueling last month.

ItzFilyO

My GS doesn't have the best MPG but the Smiles Per Gallon is unbelievable.

Knucklebus

Hmm, I have gotten well over 400 miles per tank on more than one occasion while on a trip. My recent best was 432 with 18 miles of range remaining.

I'm far from the most economical driver out there and typically cruise in the high 70s, low 80s, whatever traffic is doing.

When tooling around town, I often get low to mid 20s with the seldom seen 18-19MPG if I spend too much time in traffic.

imjohnphan

The GS 4th gen in my experience has not been as good with gas mileage. I would try replacing your O2 sensors and new engine air filters. Car could be running rich with dirty O2 sensors causing you to burn more than needed gas. Also maybe check tire pressure. I like to have a few PSI higher just to get better gas mileage.

Kingmatt24

wow, the best I’ve gotten was barely over 300 miles. But hey, it’s all about smiles per gallon for me now

ECL

With my GS350 F-Sport RWD, over the past nine years, I have never had under 25 mpg, driving 100% in town.

Knucklebus

I find there are two sweet spots for my car. Driving at 55MPH and 75MPH. Any slower than 55 and it doesn't improve. Any faster and it goes down but not by much until you get over 75. At 80 is drops by more than almost 2MPG over 75. Not scientific with documentation but my personal observations going through construction zones with a lower speed limit vs the regular interstate traffic.