KingNasGS4

iTrader: (22)

is this happening for everyone else? I know normally the highway mileage is ALWAYS better for cars. BUT my LS gets about 8.5 MPG in the city, when there is 100% city driving involved. I was wondering what was wrong with my car

I finally did a NICE 200 mile trip which the car really needed. and the car got about 32 MPG! w/ ac on most the way.

but unfortunately I dont do these trips often to be able to appreciate the gas economy.
prior to this trip, I put the car up for sale mainly due to the low mileage issues and getting laid off makes it hard to have to put in gas so often.

so does anyone else see a HUGE jump in gas economy while on the highway?

farquad

ME!
maybe not that drastic, but i do see a noticeable difference.. 6km/L city.. 10km/L hwy

Kansas

kosi718, I'm having a very difficult time believing the gas mileage figures you stated.

I drove a gen 1 LS400 from new until over 183,000 miles and I never came close to getting 32 mpg on the highway. I tracked every single gallon of gasoline that went into that car and all other cars I have ever owned and the highest gas mileage I ever got on my 90 LS400 was between 25 and 26 mpg. Usually highway-only gas mileage was between 23 and 25 mpg. City-only gas mileage could be as little as 10 - 12 mpg if I was driving in low speed 15-40 mph traffic with a lot of idling.

My 2000 LS400 with its 5 speed transmission gets slightly better gas mileage than my 90 LS did but the 00 LS still maxes out at about 27 mpg in highway only driving. Yesterday I filled the tank in my 00 LS and then drove 183 miles ... about 5 miles was at less than 45 mph and the rest was at a cruise control set 70 mph with a moderate (15-20 mph) headwind. The trip computer says the car got 25.2 mph during this 183 miles but it is usually a tenth or two high. Your 93 LS isn't going to do that well.

These are fairly thirsty cars we are driving but they still get far better gas mileage than even a medium size SUV (e.g. Ford Explorer V6 ... been there, done that) gets.

jcrome04

Have you done ANY maintenance to her? Plugs/wires, air/fuel filters??

a BIG factor on MPG is the coolant temp sensor. When I changed mine my daily avg went from 17 to 20-21. My last highway trip I got +30 MPG

at Parts.com it's a $50 OEM part. I would recommend OEM for this item.

python

iTrader: (4)

there is absolutely no way this can be true!

LiCelsior

iTrader: (32)

hey i get 16mpg. woot. driving like a grandma i can squeeze out 17....80-90% highway.

omarg

i calculate my gas mileage on every fillup. Best i've ever gotten was 29 mpg drivin 55-60 and barely touching the gas. 65-70 will get 24-25. 80+ with ac and cruise i get about 22-23

i never drive a whole tank in urban drivin but the lowest i've gotten was 14mpg.

I think the car is pretty fuel efficient all things considered.

Yotarip

I always reset the tripometer in my 93 LS at every fillup. I do a mixture of city and highway driving regularly. I run her to near empty and alway drop 18-19 gallons in her during fillups. I get between 360-380 miles on a fillup or about 20 MPG.

I guess that's good but I'm used to getting close to 30 mpg in my old camry that I sold. I just picked up a clean 1991 corolla to use as my daily but it's hard to get in that thing when the Lex is begging to be driven. If gas gets any higher the Lex will strictly be a weekend/ vacation car.

DoktorYes

I also was getting poor mileage in city. Replaced the coolant temp sensor and city mileage improved,got it at Auto Zone,about $29.00.jcrome04 is spot on.

python

iTrader: (4)

for the car to get 8 mpg it would have to be in a open loop and there would be black smoke bailing out the back! theres no way a coolant temp is going to improve it from 8.5 to 17 mpg...something isnt right with those numbers or he is leaving out info

KingNasGS4

iTrader: (22)

Yeah I've done all of those things in hope of getting better city mileage and I saw NO improvement. so when I finally got on the highway, (which i dont really travel too much driving my own car) I saw crazy numbers.

the trip one way was approx 100 miles. and in that course, the needle barely moved from F.
it went from being above the F line, where it usually is when you fill to the pump doesnt pump any more to actually being about a millimeter below the F line. ...

Ive made numerous topics on getting better gas mileage. on here and Ive used basically all suggestions that I saw.

Ive done a FULL tune up
Changed the coolant temp sensor,
Used 93 petroleum.

on the drive , I used cruise control about 75% of the way also.

lexusdude7

New here from Canada. Picked up a 94 LS in 2001. Mileage was 96,000 km. Have put on about 34,000 km as a summer driver. I can get almost 1000 km (~600 miles) per tank on the highway cruising atv 70 mph with AC on(no headwind or slight tailwind) and for sure 800 km into a headwind.

jcrome04

Maybe it's time for an "Italian Tune-up"

Maybe a full service of Seafoam.


I'd call crazy mileage in an LS anything over 30.

I was shocked when I did the math and got 30.3. The best I ever had before that was 28.9.

And yes Python the coolant temp sensor will probably not be a 100% fix. . but WILL improve fuel economy if it has never been changed, and in some cases the improvement has been drastic.

KingNasGS4

iTrader: (22)

trust me, I am as surprised as any of you all because I expected to have to refill the tank at least once because of how it usually does in the city. i was expecting about 2-3 more mpg on the highway. but not 20 mpg better.

but its too bad that Im already looking to sell the car to be able to take another long trip to retest my readings.

I still dont understand why its so terrible in the city when im using a light foot,
staying below 2000 rpm, using premium all the time and all the other methods you guys use. i just got sick of it.

JBrady

Do you have teenage kids?

Is it possible that someone is stealing your gas?

Poor city mileage of that level would suggest the gas is going somewhere other than through the engine. The check engine light would be indicating a too rich condition. Possibly a slow leak in the fuel system? Possibly a combination including a slow leaking injector that is being compensated by the computer leaning the mixture and then this programming causing the higher than range freeway mileage?

Back to the gas stealing when I was a 14 year old kid way way back in the 70s me and my buddy used to joyride our parents cars late at night as they slept. Running 100mph+ used a bunch a gas and we had to stop and refill the tank with some frequency. His dad watched gas mileage carefully and was proud to announce he was getting over 30mpg on a 1972 Plymouth Satellite with a V8 (best highway in reality of around 20mpg) of course he eventually put two and two together...