All LS400 owners with bad gas mileage READ THIS! - Page 5 - Club Lexus Forums


All LS400 owners with bad gas mileage READ THIS!

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Old 09-13-10, 10:09 AM   #61
williamb82
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im running 10-w40 oil but its hot as crap here in fl. and no, i have not changed any of the o2 sensors. figured id do this first. im filling up in the morning and resetting my trip gauge so i can see what the milage is on this next tank. i can tell already it runs and drives better and seems to have more power.
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Old 09-16-10, 09:33 AM   #62
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ECT in LS400 2000 does it called as " Engine Coolant Temperature Sender " ?
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Old 09-16-10, 11:40 AM   #63
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I dont want to mess with mine.. I get 28+ to 30 mpg on the freeway, with AC on.
and my average is 24.... stop and go city.. now my 97 and older ones never got this kind of mileage. I have not checked the 99 I just got, but I will.
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Old 09-20-10, 07:02 AM   #64
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ok, another thing i noticed this weekend. i had the upper intake manifold off as i was changing the starter, well, i pulled the egr valve and separated all the plates etc.. they were all completely clogged with carbon. even the tube into the intake manifold. i cleaned them all out. if yours is clogged you MUST remove the upper intake to clean it all out. there is a tube that goes into the intake and the outlet is right behind the throttle body. you dont want to push all that solid carbon into the manifold.

idk what the improvement of gas mileage is after cleaning this out yet as something got into an intake port and i have a bent valve so have to pull the heads. i will report my gas mileage after its all fixed though. i know its been proven that a properly working egr improves the fuel mileage on supras, so id say its likely to do the same on the 1uz
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Old 09-20-10, 12:05 PM   #65
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William any improvement you got in MPG after replace of O2 sensors? report back plz.

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Old 09-20-10, 12:45 PM   #66
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i didnt replace the o2 sensors
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Old 09-20-10, 03:19 PM   #67
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ur previous post i thought maybe!
http://www.clublexus.com/forums/5784546-post59.html

William keep us updated with the status of improvement in MPG..
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Old 09-21-10, 05:53 AM   #68
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i was referring to the engine coolant temp sensor in that post.
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Old 09-21-10, 06:48 AM   #69
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are you getting higher MPG now?
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Old 09-21-10, 07:27 AM   #70
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no, it was about the same, but the car ran much better and had more pep. however now i have to pull the heads. something dropped in an intake port when i changed the starter over the weekend and bent a valve. ugh.
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Old 09-21-10, 06:35 PM   #71
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Quote:
Originally Posted by qewani1 View Post
ECT in LS400 2000 does it called as " Engine Coolant Temperature Sender " ?
^^^What the heck^^^
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Old 10-20-10, 09:16 AM   #72
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wanted to post my results from replacing my Coolant Temp Sensor with 250k - good improvement in driveability and only took 20 minutes to replace. I know for a fact I have the bad ECU, and the new coolant sensor still made a difference.
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Old 10-20-10, 07:32 PM   #73
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Quote:
Originally Posted by Marklouis View Post
wanted to post my results from replacing my Coolant Temp Sensor with 250k - good improvement in driveability and only took 20 minutes to replace. I know for a fact I have the bad ECU, and the new coolant sensor still made a difference.
Good to hear every weekend for the past 6 months i say i will take the car by a mechanic to get this replace but it never happen yet.
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Old 10-20-10, 09:12 PM   #74
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Default Did not work for me

I replaced mine a while ago, soon after this thread first came out. I track the mileage on every tank of gas. No difference for me.

I also tested the old one (resistance vs. temp) and it was within spec. It's a pretty simple device.

So, I'm sorry to be a non-believer, but I'm sure it did not work for me. I get around 17-19 mpg in my '91 that runs perfectly.
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Old 10-20-10, 10:46 PM   #75
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Yeah my 91 gets 16 mpg city too. I think this is the max it can do. EPA says so too.

By the way I just use 87 octane now. No difference in gas mileage according to my 2 year study.
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