williamb82

is the 17-19mpg city or highway, if its highway, check your egr system, it prolly needs cleaned out.

williamb82

well, i just filled up again after all the work ive done. mileage came out to just a hair under 17mpg. this is aggravating. i cleaned the egr system out, fixed the egr pipe, replaced the coolant temp sensor, cats arnt clogged, etc... i guess now its time to replace the o2 sensors. they did appear to be original sensors when i had the engine out. ill post back the results once im able to replace them.

edit: i ordered all 4 of the o2 sensors from parts train. came out to $115 shipped. i used a coupon code "PTCART" for a 10% discount.

vietstuh

update? I just picked up a duralast coolant sensor from autozone for 14$ lifetime warranty and plannign on doing the change today.

yotoy82

I have a 1996 LS400 I just bought with 204,000 Miles on it, all the paper work, properly maintained, beautiful condition actually. The only problem I noticed when I bought it in the summer was that the engine temperature needle never went to the exact middle like my fathers 1995 LS400. Mileage was alright, 23 highway average, not horrible, not great. And I drive VERY light footed. Then when winter came, I noticed the car took FOREVER to get warm. I changed the thermostat myself, the old one was the original, the center copper part was all scratched up, I assume from jamming up. It heats up a bit faster now but doesn't go all the way to the middle unless I get on the interstate.

I also changed the air filter. I drive mostly in the city, and the last two tanks, exclusively in the city, I get about 75 miles until the needle comes to the halfway point. To put it bluntly, highway and city driving mix, I'm getting 13 mpg, and just city driving I'm getting a whopping 8 mpg!!!

Its been using 5w30 oil most of its life, but had 10w30 put in by accident when I got an oil change because forgot to mention it to the dealer, but I don't think this would make that much of a difference, although I intend to use 5w30 exclusively year round in it on the next oil change. It passed the emission testing just fine according to his paper work September 2008 at 182000 miles. No paperwork on oxygen sensors ever being changed though. No check engine lights on. It drives just fine, no funny sounds at all, smooth as butter.

Paperwork shows lexus dealership in Naperville changed the rotors, caps, wires and plugs at 144,000 miles Feb 2006, so I'm assuming they are platinum and have plenty of good life left in them!

I ordered an OEM Coolant Sensor based on this thread, should be coming in soon and am hoping thats the problem. I also ordered a new FUEL FILTER and a PCV Valve . Can anyone else tell me if I'm missing something else that I should check, any help would be greatly appreciated (my wallet would appreciate it too!)

Pic included, because its always fun seeing another LS400, Ebony Teal Pearl is beautiful.

williamb82

well, im still getting 15-18mpg. this last tank 2/3 of it was run out on cruis control. still got crap mileage. mine has had the heads rebuilt, new timing belt, new coolant sensor, new o2 sensors, ive swapp the maf, the ecu, etc... all same crappy mileage. i honestly dont have any clue what else it can be. air filter is new. oil filter and oil are new. 10w-30, trans fluid is new, tires are new and inflated properly, plugs are new, caps and rotors are recent. wires are good, car runs smooth, tps has been adjusted/replaced/adjusted again, egr has been cleaned out. Maybe the egr valve isnt working? idk. oh, and ive also run a full can of seafoam in the gas tank. no change.

yotoy82

Well you can be rest assured whenever you finally found the real culprit, you'll know almost everything is new!

williamb82

doesnt do me any good with all the extra money being thrown away due to poor gas mileage. 90% of my driving is highway back and forth to work. i commute 80 miles a day. it adds up real quick.

RA40

iTrader: (6)

May not be the engine but a driveline loss. Could be excessive drag running off the serpentine belt from a pulley, water pump... Unfortunately, the 1-LS isn't a great highway cruiser in MPG. With that kind of daily miles, the LS is outclassed by other cars.

Ours did 25.3 MPG on our 790 mile trip. Acceptable but not great with the current technology. I was reading an Audi A8 article and that car was doing 27 MPG and a tank range was ~590 miles. Amazed how some of these new big boats can be reasonable at highway speeds.

williamb82

id be ecstatic with 25mpg. instead, im getting 15-18mpg highway. i bought this car expecting 25mpg which is acceptable to me considering engine size and weight of the car.

deanshark

That's why I bought mine last year thinking I would get 25 on highway and be comfortable. I thought I was going back to work, where I was putting on almost 200 a day, but that didn't pan out and still laid off. (14 months now) Now it's less then 200 a week so the 11-14 MPG I get doesn't bother me, too much. William, did you ever do your back o2 sensors? I highly doubt they would help with your mileage but ya never know, everything else on your car is new.

williamb82

no, i didnt change them as i was told you can unplug them altogether with no change and that itll still run right if the cats are hollowed out etc... i may try to find some extra cats to hollow out and install to see if it makes a difference. i doubt it will, but who knows.

jcp2000

woo im gonna do this to my 92 and im glad one of my cousins a toyota tech i get his discount! aha

deanshark

$23 at Autozone. (Duralast) I haven't had any problems with mine yet. But if you want to spend double, go OEM. To each his own.

jcp2000

wont be double oem for me will be a little hight then the 3rd party but not 40-50

IdkUser

Could someone post up a video on how to exactly do this?