GX - 1st Gen (2004-2009) Discussion topics related to the 2003 -2009 GX470 models

feels slightly sluggish and slight decrease in mpg

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Old 09-02-13, 06:37 AM
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GreggyG
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Default feels slightly sluggish and slight decrease in mpg

I have an 06 sport edition with 83k miles. Never a problem or complaint. If I'm not going crazy, I think that I am noticing a very slight performance decrease. I bought this with 63k miles on it and I'm not 100% sure what servicing was done before. Any ideas of where to start, spark plugs or something like that? Thank you.
Old 09-02-13, 07:07 AM
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cssnms
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The spark plugs should be good until 90k, but you're close so it might be worth just replacing them now.

Otherwise, try running a coulple of bottles of Chevron Techron fuel system cleaner through your tank back-to-back. After that add a bottle once per month to maintain.

Lastly, check your tire pressures too.
Old 09-02-13, 08:23 AM
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Crispy3M
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Originally Posted by GreggyG
I have an 06 sport edition with 83k miles. Never a problem or complaint. If I'm not going crazy, I think that I am noticing a very slight performance decrease. I bought this with 63k miles on it and I'm not 100% sure what servicing was done before. Any ideas of where to start, spark plugs or something like that? Thank you.
Like Chris said, plugs may need to be changed.

Also make sure your air filter is changed on a regular basis and good clean gas.

Any chance you have recently started getting gas at a different location?

One last tip... If a tanker truck is filling the station's tank at the time you want to buy gas, do not fill up; most likely dirt and sludge in the tank is being stirred up when gas is being delivered, and you might be transferring that dirt from the bottom of their tank into your car's tank.

Cheers!
Old 09-02-13, 08:41 AM
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GadgetRick
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Originally Posted by Crispy3M
Like Chris said, plugs may need to be changed.

One last tip... If a tanker truck is filling the station's tank at the time you want to buy gas, do not fill up; most likely dirt and sludge in the tank is being stirred up when gas is being delivered, and you might be transferring that dirt from the bottom of their tank into your car's tank.

Cheers!
I've heard many people say this, however, you have a fuel filter which will catch anything like this. It may muck up your fuel filter faster than normal but it won't affect the performance of your engine because the filter keeps any of that crap from getting to your engine.

Not saying it's bad advice, just saying it has nothing to do with performance.
Old 09-02-13, 08:56 AM
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Crispy3M
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Originally Posted by GadgetRick
I've heard many people say this, however, you have a fuel filter which will catch anything like this. It may muck up your fuel filter faster than normal but it won't affect the performance of your engine because the filter keeps any of that crap from getting to your engine.

Not saying it's bad advice, just saying it has nothing to do with performance.
I guess I should have been more specific... A clogged fuel filter will definitely affect performance.

Cheers!
Old 09-02-13, 09:20 AM
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GreggyG
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thank you for your suggestions, I'll also look at my air filter. I am using a K&N but I should probably go back to stock and look at the MAF sensor to clean as well. Where is the fuel filter?
Old 09-02-13, 11:41 AM
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Originally Posted by GreggyG
thank you for your suggestions, I'll also look at my air filter. I am using a K&N but I should probably go back to stock and look at the MAF sensor to clean as well. Where is the fuel filter?
Sorry, I may have sent you on a wild goose chase. I just did a quick search and there may be a chance it's located inside the gas tank?

I remember when they switched them from the carb to the fuel rail. Now the tank? If that's the case, score one more for engineering that requires the customer to pony up more cash at the dealership.

Chris
Old 09-02-13, 03:32 PM
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Don't clean the AFM.
Old 09-03-13, 06:36 AM
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RCsGX
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Originally Posted by GreggyG
I bought this with 63k miles on it and I'm not 100% sure what servicing was done before.
You can check your service history here: https://secure.drivers.lexus.com/lex...-lexus/home.do

My GX was a 1 owner before me and the lady religiously serviced it at our local Lexus dealer. I have all the records from day 1. Since owning it I've taken it to Toyota twice for an oil change and when I was in a pinch I took it to Valvoline for an oil change. Toyota reported on my records but Valvoline did not.
Old 09-03-13, 09:13 AM
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Matsui
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Originally Posted by RCsGX
You can check your service history here: https://secure.drivers.lexus.com/lex...-lexus/home.do

My GX was a 1 owner before me and the lady religiously serviced it at our local Lexus dealer. I have all the records from day 1. Since owning it I've taken it to Toyota twice for an oil change and when I was in a pinch I took it to Valvoline for an oil change. Toyota reported on my records but Valvoline did not.
I recall you were experiencing issue some time ago with major drop in MPG. Were you able to find the root cause and fix it?
Old 09-03-13, 01:19 PM
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RickC5
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Originally Posted by RCsGX
You can check your service history here: https://secure.drivers.lexus.com/lex...-lexus/home.do

My GX was a 1 owner before me and the lady religiously serviced it at our local Lexus dealer. I have all the records from day 1. Since owning it I've taken it to Toyota twice for an oil change and when I was in a pinch I took it to Valvoline for an oil change. Toyota reported on my records but Valvoline did not.
Interesting..... Service work done on our Lexus at our local Toyota dealer (lots of it) has NEVER been reported on the Lexus database.
Old 09-03-13, 03:03 PM
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RCsGX
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Originally Posted by Matsui
I recall you were experiencing issue some time ago with major drop in MPG. Were you able to find the root cause and fix it?
There was no drop, since owning it I was always getting between 11-12mpg w/ the 17" wheels and the 18" wheels. The 17" wheel and tire weighed 64.4lbs.; the 18" wheel and tire weighed 69lbs. / difference of 4.6lbs.

I did everything I could think of and the MPG's did not change so it is what it is.

New spark plugs
New air filter
New front O2 sensors
MAF from my Tundra (cleaned old GX MAF)
New PCV valve
New fluids except transmission
Brakes checked by Toyota = OK
Axles checked by Toyota = OK
4 wheel alignment by Toyota
Fuel injection flush by Toyota



Originally Posted by RickC5
Interesting..... Service work done on our Lexus at our local Toyota dealer (lots of it) has NEVER been reported on the Lexus database.
That's weird. I didn't even tell Toyota to update it, they just did but for some reason their dealer name doesn't show up but Lexus's dealer name does?






Maybe ask your Toyota dealer to update just so it's there for future reference.
Old 09-03-13, 06:18 PM
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YoshiMan
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Hmmm... I just looked it up, and the fuel filter IS inside the tank!

I haven't gotten my Service manuals yet, so does anyone happen to know if these have the access panel inside the truck in order to get to the fuel pump? or do you have to drop the whole tank?
Old 09-05-13, 01:06 AM
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mann777
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You can access if you drop the 5th Tire. They are attached to the tank, as once i had to fix them for a vacuum leak.
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