Very low MPG
09-08-21, 08:29 PM
#31
I think you have your tire pressure/tire wear backwards.
Too much air pressure will bulge the tire, causing center wear.
Too little air pressure will allow the tire to fold in the middle slightly and wear the inner and outer edges.
As far as alignment, toe-in or toe-out are the ones that affect mileage the most. Caster has absolutely no impact on mileage (handling, yes) and camber has very little unless it is extreme as in more than 4° +/-.
If the car is toed-in too much, you will wear the inner edges the tires will be "snow plowing" as you try to go forward. If it is toed-out, you will wear the outer edges unless you camber is hugely off.
One additional thing to check is your brakes. Check to be sure you calipers aren't sticking. Even a little bit will put a drag on the mileage.
Too much air pressure will bulge the tire, causing center wear.
Too little air pressure will allow the tire to fold in the middle slightly and wear the inner and outer edges.
As far as alignment, toe-in or toe-out are the ones that affect mileage the most. Caster has absolutely no impact on mileage (handling, yes) and camber has very little unless it is extreme as in more than 4° +/-.
If the car is toed-in too much, you will wear the inner edges the tires will be "snow plowing" as you try to go forward. If it is toed-out, you will wear the outer edges unless you camber is hugely off.
One additional thing to check is your brakes. Check to be sure you calipers aren't sticking. Even a little bit will put a drag on the mileage.
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Knucklebus (09-10-21)
09-08-21, 08:37 PM
#32
I think idling is not the killer of fuel mileage with the GS 350. I believe you could idle the engine for many hours on-end and really not burn much fuel - of course you'd travel zero miles so the fuel mileage would in essence be zero. I think what kills fuel mileage with the GS 350 is practically any positive throttle that accelerates the car - even minimal, gentle acceleration seems to make fuel mileage suffer beyond what is expected. Maintaining a slow constant speed of around 40 mph seems to produce quite good fuel mileage. As does maintaining a constant highway speed of around 60-70 mph. However, push on that throttle pedal to briefly accelerate (increase ground speed) even just a little bit and fuel mileage drops drastically...
09-09-21, 04:17 AM
#33
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I have a 2011 Lexus GS350. I do 59 on the highway. I don't push the car in the city. I don't hav a heavy foot and use cruise often. Don't plant my foot starting from stop signs or lights. I am quite happy with the fuel consumption. The Gs350 is a pestige car not a race car and needs to be handled like a women. carefully.
09-09-21, 11:09 AM
#34
Driver School Candidate
Thread Starter
I think idling is not the killer of fuel mileage with the GS 350. I believe you could idle the engine for many hours on-end and really not burn much fuel - of course you'd travel zero miles so the fuel mileage would in essence be zero. I think what kills fuel mileage with the GS 350 is practically any positive throttle that accelerates the car - even minimal, gentle acceleration seems to make fuel mileage suffer beyond what is expected. Maintaining a slow constant speed of around 40 mph seems to produce quite good fuel mileage. As does maintaining a constant highway speed of around 60-70 mph. However, push on that throttle pedal to briefly accelerate (increase ground speed) even just a little bit and fuel mileage drops drastically...
You're SO right about this. Two days ago, I filled up right before getting on the highway and I’ve been averaging around 18 MPG ever since. The last two days, I’ve only been driving to and from work. And I’ve been very mindful not to take off and accelerate rapidly which I tend to do occasionally. I once glanced at my MPG after “flooring it” to pass a group of slow moving cars and I swear my MPG dropped from 18 to 17 in like 2 seconds. It’s the rapid acceleration that is a real killer of fuel economy.
09-09-21, 01:03 PM
#35
Lexus Test Driver
You're SO right about this. Two days ago, I filled up right before getting on the highway and I’ve been averaging around 18 MPG ever since. The last two days, I’ve only been driving to and from work. And I’ve been very mindful not to take off and accelerate rapidly which I tend to do occasionally. I once glanced at my MPG after “flooring it” to pass a group of slow moving cars and I swear my MPG dropped from 18 to 17 in like 2 seconds. It’s the rapid acceleration that is a real killer of fuel economy.
Last edited by bclexus; 09-09-21 at 01:09 PM.
09-09-21, 02:04 PM
#36
I am surprised that're pretty poor gas mileage. I remember it being a little better than that. Hell my Corvette gets way better gas mileage at around 22-24mpg in city driving and that's a V8 with 460HP lol.
09-09-21, 05:14 PM
#37
Interesting, I previously had a 14 GS as well and was convinced something was wrong as I only would get 13-15 mpg on average, car drove totally fine and only had 50k miles, my brother who has a 15 GS would consistently get 4-5 mpg more than me on similar drives. I never figured out why that car got such low mileage, I even changed the plugs but it didn’t help. I have a 16 GS now and I usually get about 18-19 mpg on the same commute and can get 26-27 on highway trips fairly easily.
09-09-21, 08:35 PM
#38
Lexus Test Driver
I think the answer to the fuel mileage enigma lies in how Lexus fashioned the ECU for the GS 350 engine to perform at peak performance at times of driver induced throttle response with performance tweaked ignition and camshaft (valve) timing, plus transmission shift parameters - all of which are not conducive to achieving admirable fuel mileage. The ECU for the ES 350 engine, on the other hand, doesn't perform at this same peak performance like that of the GS 350, thus the 'executive' model ES 350 doesn't suffer from poor fuel mileage nearly as badly as the 'sporty' GS 350 model does - and with that in mind the car maker only recommends regular gasoline for the ES 350 whereas the car maker recommends premium gasoline for the GS 350. Whether you are in ECO, Standard or Sport drive mode the GS 350's engine and transmission is ready to perform at its best at the slightest heavy touch of the accelerator. In fact, you can drag race a GS 350 at WOT (wide open throttle) in all three drive modes (with the transmission in either Drive or Manual - and shift it manually or just let it upshift at redline) - and for all practical purposes the end results will be the same for technical reasons as Lexus purposely designed its higher performance into the GS 350's ECU. And, that is the reason I think the GS 350 doesn't get the fuel mileage one might expect it to achieve at first thought and consideration...
Last edited by bclexus; 09-10-21 at 08:58 AM.
09-10-21, 07:10 AM
#39
I think the answer to the fuel mileage enigma lies in how Lexus fashioned the ECU for the GS 350 engine to perform at peak performance at times of driver induced throttle response with performance tweaked ignition and camshaft (valve) timing, plus transmission shift parameters - all of which are not conducive to achieving admirable fuel mileage. The ECU for the ES 350 engine, on the other hand, doesn't perform at this same peak performance like that of the GS 350, thus the 'executive' model ES 350 doesn't suffer from poor fuel mileage nearly as badly as the 'sporty' GS 350 model does - and with that in mind the car maker only recommends regular gasoline for the ES 350 whereas the car maker recommends premium gasoline for the GS 350. Whether you are in ECO, Standard or Sport drive mode the GS 350's engine and transmission is ready to perform at its best at the slightest heavy touch of the accelerator. In fact, you can drag race a GS 350 at WOT (wide open throttle) in all three drive modes (with he transmission in either Drive or Manual) and for all practical purposes the end results will be the same for technical reasons for which Lexus purposely designed into the GS 350's ECU. And, that is the reason I think the GS 350 doesn't get the fuel mileage one might expect it to achieve at first thought and consideration...
09-10-21, 07:26 AM
#40
Instructor
I think the answer to the fuel mileage enigma lies in how Lexus fashioned the ECU for the GS 350 engine to perform at peak performance at times of driver induced throttle response with performance tweaked ignition and camshaft (valve) timing, plus transmission shift parameters - all of which are not conducive to achieving admirable fuel mileage. The ECU for the ES 350 engine, on the other hand, doesn't perform at this same peak performance like that of the GS 350, thus the 'executive' model ES 350 doesn't suffer from poor fuel mileage nearly as badly as the 'sporty' GS 350 model does - and with that in mind the car maker only recommends regular gasoline for the ES 350 whereas the car maker recommends premium gasoline for the GS 350. Whether you are in ECO, Standard or Sport drive mode the GS 350's engine and transmission is ready to perform at its best at the slightest heavy touch of the accelerator. In fact, you can drag race a GS 350 at WOT (wide open throttle) in all three drive modes (with he transmission in either Drive or Manual) and for all practical purposes the end results will be the same for technical reasons for which Lexus purposely designed into the GS 350's ECU. And, that is the reason I think the GS 350 doesn't get the fuel mileage one might expect it to achieve at first thought and consideration...
09-10-21, 07:55 AM
#41
Gentlemen, what makes your actual MPG numbers even worse is that all of you likely used E10 gasohol. That would drop the numbers even more. For example it was 18.5 it would be 17.4. Also, That is in theory, but in reality for my car it is closer to 10% loss.
09-10-21, 09:30 AM
#42
https://en.wikipedia.org/wiki/MTBE_controversy
09-10-21, 09:47 AM
#43
Lexus Fanatic
What kills fuel mileage with the GS 350 is practically any (I mean literally any) positive throttle that accelerates the car - even minimally. Even the most gentle acceleration makes fuel mileage suffer. If you get in the habit of acting as though there is an open tube of toothpaste or a fresh egg between your foot and the gas pedal you'll see much better fuel mileage. While not as much fun, it'll save you money at the pump and you won't visit your tire dealer as often...
With gas prices rising since Jan and getting worse/staying high I don't drive as aggressively though and try to combine trips/errands, not drive as much, the trips to the pump are a little painful.
09-10-21, 09:55 AM
#44
Lexus Fanatic
3rd Gen GS350 was also putting out quicker 0-60 times and felt quicker then the 4th Gen GS350, I thought they may have adjusted gearing for the 4th Gen to get better mileage but I guess not if you get better mileage in the 3rd Gen. The 4th Gen is a wider larger looking car then the 3rd Gen, more luxury/performance features so maybe it is the extra weight, larger wheels.
09-10-21, 11:15 AM
#45
Lexus Test Driver
LOL, I would just get a corolla or Honda civic with the smallest most economical engine and turn the AC off in the middle of summer if I want that experience and to save as much on gas as possible. I stopped putting it in eco mode because I didn't like the weaker throttle/acceleration. It really defeats the point of getting a largish, heavy luxury car with a 300hp+ engine barely using the power just to save some money at the pump/on tires. I don't like wasting money and if I can save money on gas/tires within reason I will try to do it but I still like to enjoy the power and smoothness too. I knew when I got my GS430 and GS350 they were not going to get very good mileage aside from highway, I still wanted the power and performance, I just try to drive them less, luckily most of the time I have owned them gas prices were pretty low.
With gas prices rising since Jan and getting worse/staying high I don't drive as aggressively though and try to combine trips/errands, not drive as much, the trips to the pump are a little painful.
With gas prices rising since Jan and getting worse/staying high I don't drive as aggressively though and try to combine trips/errands, not drive as much, the trips to the pump are a little painful.