Gas Mileage Can It Get Any Better

[914lps]

I have a 91 LS 400. Get around 17 in the city and 22 on the highway.

I check tire presure and keep it good.

Change oil every 3,000 miles

Tune up as needed (put new plugs, wires, coils etc.. on about 15,000 miles ago when I did TB).

Run 91 Octain ( get less power and mpg with low Octain)

Keep overdrive on and power setting to Economy.

Pull and clean airfilter one a month or after a long drive of 800 to 1,000 miles

Try to not lead foot it.

Anyone know of other ways to get better MPG out of a 91 LS???

Have any of you added any after market parts and gotten better MPG?

Thank you all.

[Tousij2]

I have a 91 LS 400. Get around 17 in the city and 22 on the highway.

I check tire presure and keep it good.

Change oil every 3,000 miles

Tune up as needed (put new plugs, wires, coils etc.. on about 15,000 miles ago when I did TB).

Run 91 Octain ( get less power and mpg with low Octain)

Keep overdrive on and power setting to Economy.

Pull and clean airfilter one a month or after a long drive of 800 to 1,000 miles

Try to not lead foot it.

Anyone know of other ways to get better MPG out of a 91 LS???

Have any of you added any after market parts and gotten better MPG?

Thank you all.

Hello,

The mileage you are obtaining is exactly where u should be + or - 3.

Good luck,

JT

[914lps]

Thank you. I know I'm getting the MPG i should be in fact I'm almost on the governments MPG rating. But I would like to get better MPG. Gas is again ging down, but this time next year it will hit the $4.00 mark at the cheepest... In fact 20 miles from me one station is still at 4.25 per gallion over the boarder in California.

Here in AZ it is down to 3.11 from 3.25 So more MPG would be nice.. And yes I know for thw wieght power etc... and beibg a 91 this is very nice MPG to be getting as most "new" cars in this class get 26 to 28 hwy ratings at best.

[yidaitianjiaous]

Gosh! i goona only around 10 mpg... what's the problem.... by the way, did u fill up the tank to full or just half of it? any difference for mpg?

mine is toooooo lowwwwwwww

I have a 91 LS 400. Get around 17 in the city and 22 on the highway.

I check tire presure and keep it good.

Change oil every 3,000 miles

Tune up as needed (put new plugs, wires, coils etc.. on about 15,000 miles ago when I did TB).

Run 91 Octain ( get less power and mpg with low Octain)

Keep overdrive on and power setting to Economy.

Pull and clean airfilter one a month or after a long drive of 800 to 1,000 miles

Try to not lead foot it.

Anyone know of other ways to get better MPG out of a 91 LS???

Have any of you added any after market parts and gotten better MPG?

Thank you all.

[IS400]

You have to remember that you are moving a relatively large car around with a 4.0 liter engine and an automatic transmission. The engine is a thirsty design. To get 250 horsepower out of that small of a displacement lexus equiped it with 4 valves per cylinder and overhead cams. Guys have turbo charged it and gotten 800 horsepower with a STOCK bottom end and just reworked heads and intake/injectors etc. It was a high tech design when introduced and incorporated many racing car (formula 1) technology in its architecture. That is why it is so durable also.

5.0 Mustangs have on average 225 horsepower and most dyno'd much lower when tested.

We (mine is a 1990) get 250 with a full liter less displacement.

[VMF]

try to put higher octane fuel.

but 17 mpg is a very decent mileage for the 16 year old car with a 4.0 engine.

my friend with a year old infinity m35 gets only 10-12 mpg on a 3.5 engine and he is not foot heavy:)

so i dont think you should be worried about the mileage.

this kind of mileage is expected when you buy a heavy car with a moderately big engine.

when i asked a service person same question few years back he said "people who buy lexus dont really care about the mileage" :)

[Tousij2]

when i asked a service person same question few years back he said "people who buy lexus dont really care about the mileage" :)

I guess I would not agree wih this statement, just becasue I can afford it does not mean I don't care how my car performs in this category.

I would actually say Lexus Owners are more educated in their purchases and base allot of their decision on this factor allong with reliabilty.

I would say that statement may be geared more toward a Hummer or Escalade owner.

Just my .02

JT

[SRK]

Fuel consumption is determined to a great extent by the weight of the vehicle. There are other factors that have been mentioned, tires, drag, and certainly more like transmission ratios and so on, but weight is the big one. Given that the engine runs at near stoichiometric fuel/air ratio all the time, there is little else that can be done except to ensure the state of tune is good. Once those small variables are optimized, you're done as far as improving mileage is concerned.

If that doesn't do it for you, you'll have to buy a smaller car.

As to whether or not Lexus owner's are concerned about fuel mileage, it's obvious the original owner's were not. When a vehicle depreciates as quickly as even a Lexus does, say 50% in five years, the original owners were looking at perhaps $25k in capital loss. That's buys one helluva lot of fuel, and if one wanted to save money -in total - on transporation, I'd have bought a 72 Ford LTD with the biggest engine I could find, for $500.00 bucks and drive the crap out of it. You'd never burn the 25k plus the Lexus fuel cost over the average mileage a 351C would give.

It's the second and third owners that care about mileage I think, because we are too cheap or poor to have bought the car new. So some whine about mileage.

I don't. I think 22mpg imperial in town is great. I think 30mpg imperial on the highway is great. And I don't care about my friends who brag about 45mpg in some little crapbox car. I won't drive a crapbox. I drive Lexus, and always will from now on. My only regret is that I didn't drive these cars sooner.

[VBdenny]

My 1990 LS gets around 18 MPG in city and slightly over 25MPG highway traveling between 60-85MPH. I use Mobil 1 which I think helps, a K&N air filter which does help and keep 34lbs air pressure in my BFG Traction T/A V 225/60VR-15 tires. If it was a lot worse, I probably would still drive the car. I paid $3.03 for Premium this week at Texaco.

[914lps]

SRK

I loved your response.....

I have been looking into what would I replace the "Lexus with"... If I was going to... OK a nice under powered 4 banger gives me that great MPG... Or the odd 3 bangers that are out there.... But they go so slow... Can't get up a hill around here and even hit 65 MPH, and have no inside space and the ride is not that great...... Unless you turbo the things... But if you do, you drop that MPG down into the mid 20's... And for a few more MPG, I ant giving up all the LS offers me!

I really don't get it....Only the 4 bangers get the really nice MPG... If you go to a 6... Most of them get gas mileage below what some 8's give you........

My friend bought a used 2002 caddy with a nice 8 cyl. eng. In town only 18 MPG, but on the hwy he gets 30+ He gets power comfort and size and better MPG then any 6 cyl, and even better then a lot of turbo 4's!

I know the reason is a lot of high tech stuff on that 8, and the fact that it cuts to 4 cyl, depending on the need....

But you would think that if you can get 30 out of a caddy, with 8 cyl.. and all that weight... A six should give you at least 40+!

Have some fun and play the what I'm I going to buy game...

Go to :

http://www.fueleconomy.gov

You can look up any car sold in the US from 1985 up, and see the MPG..... It will show that very few cars that have good power and comfort get even 20 MPG, or are not much better the 91 LS...

Boy have we gone of the subject of my posting...

I really just wanted to know if anyone had gotten a few more MPG more out of the LS and "how".....

I will admit I did not expect a positive response as with the eng design and electronics it's not like there is anything to tinker with....

Thank you all... SRK... Yu said it.... Unless you have to and have no choice about it.... Who wants to ride in a little $#@!^%$

[a squirrel]

Well, I also have a 91 LS, and the sticker that was on the car said 18 Streets 23 Highway. I get 12ish on the streets, and 18 highway. It is a V8, so im suprised it gets that high. However I do have a lead foot, so thats why. I keep up on matience, and have 160,000 miles. I would suggest keeping the windows closed for aerodynamics, and turning off AC/Heater because I'm sure that affects the mileage.

[fencera]

1. Replace your PCV valve.

http://www.lexls.com/tutorials/emission/pcv_valve.html

2. Look into a K&N air filter. They can help.

3. If you're really desperate (or just next time), change your spark plugs. I am currently using Brisk LGS plugs. Little known company, but their product is great. 1-2 MPG more over what I was getting before. Also seem (?) to result in slight performance increase. Who knows about that part...

Cleaning your throttle body may also help. I am not sure if that has any potential fuel efficiency benefits or just general smoothness.

I guess that's pretty much it, not much different than what you originally listed. My '90 LS400 with over 305,000 miles is getting about 25 on the highway and about 20 in the city. I generally don't drive gently, but I do almost entirely highway driving.

Hope that helps.

[Bali26]

The oxygen sensors

[sonyman]

try to put higher octane fuel.

but 17 mpg is a very decent mileage for the 16 year old car with a 4.0 engine.

my friend with a year old infinity m35 gets only 10-12 mpg on a 3.5 engine and he is not foot heavy:)

so i dont think you should be worried about the mileage.

this kind of mileage is expected when you buy a heavy car with a moderately big engine.

when i asked a service person same question few years back he said "people who buy lexus dont really care about the mileage" :)

He's running 91 octane already, which is the recommended octane according to the owner's manual. I also don't believe that 1991 LS400's are capable in stock form of advancing the timing further when they detect even higher octane ratings.

However, I do agree with VMF that your mileage is fine. Replacing oxygen sensors etc. is a waste IMO considering it would yield such a small improvement since you are already getting decent mileage for that car.