Poll: Ls Fuel Economy

[eatingupblacktop]

Since there's been a lot of discussion about fuel economy lately, especially in light of recent prices, I thought it would be interesting to compile some numbers on what kind of economy owners are getting with the LS.

Me first - My stats:

Average about 29-30 mpg @ 100-110km/hr. I've hit 31 a few times. The best was 33.29 mpg or 8.84L / 100km. Must have been on a grade or with a tail wind.

Worst was 19 mpg with mostly city. Average over the year has been a combined 25 mpg.

Always premium -min quarter tank / 33 psi / moderate acceleration/braking / tuned / clean air filter / fresh fluids / best - windows closed, a/c off, no pass; worst - windows/roof open, a/c off, w pass.

These numbers surprise me. Better than my 6 cyl Volvo. I've used different gas stations at different times of the day, and crunched the numbers twice to make sure. I'd like to know if there's anyone else getting numbers similar to mine.

[NewGuy19]

I have yet to break 28mpg on the highway, and average 19mpg in town. I typically drive with my windows down and the top open when I'm driving around town but keep my windows up and just the vent on when I'm on the highway.

My worst average was 7.8mpg last winter where i only put on 128 miles and put in 16 and some odd gallons. Guess you burn a little gas letting you car warm up from 25 below.

My car is by no means mint anymore. It's a '90 with 138k on it. The plugs, wires and rotors have never been replaced, but that's on the list to do before winter. Maybe then I can finally break that infamous 30mpg mark.

[jcrome04]

The LS is amazingly efficient! B)

The best I've ever had is 29.3mpg and that was before some big maintenance issues were taken care of. The worst I got was 18-19mpg, that was a lot of lead footed city driving.

I want to get on the highway and take a long trip. Set the cruise.. and watch the mileage rack up :)

[blake918]

My '99 LS with 167k (well maintained and no mods of any kind) gets 13mpg in the city (5-10 minute trips, stop and go, staying under 40mph etc. Light foot.), and 28.5mpg on the interstate with the cruise set near 80mph and the a/c full blast 9 or 10 months out of the year. I wish I could slow it down to 70mph to see if it would hit 29-30mpg on the interstate, or even higher if I would stay on back roads going 60mph--those speed trap infested back roads are like torture though.

As good as the mileage is, it kills me that 80mph = 2,600rpms. Imagine if 80mph was only 2,000-2,200 rpms like it is in most cars....

[eatingupblacktop]

My '99 LS with 167k (well maintained and no mods of any kind) gets 13mpg in the city (5-10 minute trips, stop and go, staying under 40mph etc. Light foot.), and 28.5mpg on the interstate with the cruise set near 80mph and the a/c full blast 9 or 10 months out of the year. I wish I could slow it down to 70mph to see if it would hit 29-30mpg on the interstate, or even higher if I would stay on back roads going 60mph--those speed trap infested back roads are like torture though.

As good as the mileage is, it kills me that 80mph = 2,600rpms. Imagine if 80mph was only 2,000-2,200 rpms like it is in most cars....

Wow, 28.5 mpg @ 80 mph! That's terrific. If I go north of 75, I notice the mileage drops quite a bit, more the higher I go. Even so, it's nice to cruise at these speeds once in a while - to stretch those long legs despite the gearing. The car is built for the wide open highway. Driving it in the city is like a whale in an aquarium - just itching to bust out into that vast ocean and cruise the planet! Makes me want to go out for a drive right now! :)

[Captain Meeks]

WOW..!!! 28.5mpg..thats great...my 94 with 139,000 miles average between 18 to 25 depending on driving..wifie seems to par better than I do.. lol... but still great considering the V8 and we do always run premium ...very happy with that though

[killerFatty]

If you all are getting in the 20's howcome i get 10 in the city on premium with my 93 179K just tuned up?? I have heard the thermostat could be causeing it or the coolent temp. sensor? which if either should i replace first? any advice would be great. THX

[jcrome04]

What is "tuned up"??

[Captain Meeks]

When you say tuneup..? what specific's are you speaking of...we talking new plugs...or Lexus service..?..Just wondering,I noticed on other threads that after service some complained of gas mileage being under par... after discussing the service there was some filter or injection problem that was not addressed during service... please dont get offended..just asking to find out further information on your question.

[killerFatty]

I took her to a dealer and had a tune up done and all the fluids flushed, however gas milage has been poor even before the service. I have heard that the coolent temp sensor or the thermostat may be to blame. any ideas?

[Captain Meeks]

I cant answer that one on the thermostat.....I do know that a oxygen sensor made the 96 LS I had get real bad gas mileage.. there are alot more educated people in here than me on the issues...and there are alot of threads that I have seen in the past on the exact same issue. Look back in the past threads and see because I have heard some of the exact same statement you just made... if you find one they might be able to tell you if they got better results with the changes they made... could be more cost effective then changing sensors without any change. I will ask around too... 10 mpg just dont sound right... :) :) ..let ya know if I come up with anything.

[jcrome04]

If an 02 sensor is bad it will throw a code....

[GKLCPA]

Just got back from a roundtrip to florida of about 1200 miles. I averaged about 25 mpg overall. The best I got was on one leg of the trip when I hit 26 mpg. I've got a 96, so I don't have the 5th gear.

This is one hell of a car.

[jcrome04]

How fast were you going? 75-80?

[killerFatty]

I cant answer that one on the thermostat.....I do know that a oxygen sensor made the 96 LS I had get real bad gas mileage.. there are alot more educated people in here than me on the issues...and there are alot of threads that I have seen in the past on the exact same issue. Look back in the past threads and see because I have heard some of the exact same statement you just made... if you find one they might be able to tell you if they got better results with the changes they made... could be more cost effective then changing sensors without any change. I will ask around too... 10 mpg just dont sound right... :) :) ..let ya know if I come up with anything.

since there is no O2 sensor codes i went ahead and got the new thermostat and coolent temp sensor from Autozone and plan to put them in this weekend. I'll let you guys know of any improvements.

[jcrome04]

Sounds good!

How much were they?

Is it ok to use these and not OEM?

[GKLCPA]

How fast were you going? 75-80?

Yes. I was averaging in that range

[killerFatty]

Sounds good!

How much were they?

Is it ok to use these and not OEM?

IMO it's fine to use autozone non OEM, however some disagree. I just don't see how doubling the price for the same part will make a major diffrence. I just put in the coolent temp. sensor, but i haven't had time to drain coolent and put in the thermostat. I am however getting significantly better milage. I'm not exactly sure what kind of #'s yet b/c i havent filled my tank all the way up, But I cant watch the fuel gauge go down anymore. I also took 2.5 seconds off my 0-60 time. With this result i might just tak the thermostat back and get my $10 back. One more thing, If any of you guys put in a new temp. Sensor, make sure you have a really deep socket so you dont leave 3/4 inch of thread sticking out and wonder why there is a puddle of coolent in your driveway. lol :D

Thermostat $10

Thermostat gasket $2

silicon sealer $4

coolent Temp. Sensor $30

[DobieG]

Recent trip from SoCal to Vegas got me 28.8 mpg, air on almost the entire time, considering it topped out at 109 degrees in Baker. yikes!

when possible, had cruise control set at 75 - only went over that mph once, when passing someone.

2001 LS430

[jcrome04]

Are there any DIYs to changing the thermostat and coolant temp sensor?

[killerFatty]

Are there any DIYs to changing the thermostat and coolant temp sensor?

Yeh there is a great thread on club lexus about the coolent temp. sensor and lexls.com has one on the T-stat. I don't remember the name of the thread on CL, but i did put together a word doc. comprised of both repairs. give me your email and I'll shoot it on over to ya

[cardona6569]

Hello: The best economy are in the 90-06 models, even as the new models are nice they do not give the same economy, but they tend to be more powerful. Even the LS 600 gives kind of a poor fuel economy, they said in a magazine that to recoup the money the car would have to be over 50 years old or more, I still buy one if I had the money, but would expect Lexus to make the more eficient, not because the price of fuel but because the impact on the quality of the air, this is with the understanding that Lexus are makers of cars with that have some of the lowest emissions on the road.

[90LS400Lexus]

When I got my LS (1991) a year ago, I was consistantly getting 21.1 MPG. NOW when I have only recently started checking it, I am down to a lousy 15.9 MPG - consitantly. I have switched stations where I get the fuel, so maybe its a lower grade of fuel or something.

[baldeagle100]

Since there's been a lot of discussion about fuel economy lately, especially in light of recent prices, I thought it would be interesting to compile some numbers on what kind of economy owners are getting with the LS.

Me first - My stats:

Average about 29-30 mpg @ 100-110km/hr. I've hit 31 a few times. The best was 33.29 mpg or 8.84L / 100km. Must have been on a grade or with a tail wind.

Worst was 19 mpg with mostly city. Average over the year has been a combined 25 mpg.

Always premium -min quarter tank / 33 psi / moderate acceleration/braking / tuned / clean air filter / fresh fluids / best - windows closed, a/c off, no pass; worst - windows/roof open, a/c off, w pass.

These numbers surprise me. Better than my 6 cyl Volvo. I've used different gas stations at different times of the day, and crunched the numbers twice to make sure. I'd like to know if there's anyone else getting numbers similar to mine.

[baldeagle100]

ls 400 1995, everything is tuned up. Just did a 4443 mile vacation trip and averaged 27.6 for the trip. Best mileage was coming down from Idaho to Texas 31.4 and 33.1 miles per gallon on 2 complete tankfuls. Worst tankful was 23.9 on the trip. I bought gas at the UTE indian casino in Colorado. Must have not been good gas. Now for you purists, this was all regular gas 85 to 90 octane depending on the station. Part of this run was to see if there was a difference in premium gas and it did not make any difference at all. Prices paid were from 3.13 down to 2.68 per gallon on regular gas. Dates were april 28 to may 21st 2010. Several stations had the "may have up to 10% ethanol" signs on the pumps and the mileage did not indicate any problem or advantage to the ethanol. So no help there....