Do You Use Premium Gas In Your Es 300?

[NW Sooner]

My manual says to use premium, but a friend said I could use regular unleaded without any problems.

Anybody have any bad experiences with regular unleaded gas?

[SKperformance]

too many threads ,

this is a repeated question like oil being synthetic or not.

PAY ME NOW ,OR PAY ME LATER..........

It is the only mantra

[NeiLtYmE]

hint = Search

[turnbowm]

My manual says to use premium, but a friend said I could use regular unleaded without any problems. 

Anybody have any bad experiences with regular unleaded gas?

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The owner's manual for the wife's '98 ES300 specifies 87-octane (i.e., regular) unleaded. Have tried premium, but there was NO difference in performance. Same thing with our friend's 2000 and 2001 ES300. Am surprised that your manual said to use premium. Recently, looked into buying a new 2005 ES330 and it called for regular also.

Martin

[Beer Dave]

I have a '99 ES 300 and it also say 87 octane is fine. But I have noticed that when I use premium I get about 30 miles per tank of gas or almost 10% increase in mileage. Since premium costs about 10% higher than regular your paying about the same amount. At least that has been my experience. Also lots of posts showing O2 sensors, etc. lasting longer using premium.

[SKperformance]

It takes more than one tank to see any difference in octanes as well as the carbon affect of reg gas.

[timothy]

I run Mobil 89 octane in my 04 es 330, about every other tank I run 93. A GM tech. told me Mobil was about the best gas. Does Lexus say anything on which brand of gas to use?

Timothy

[chuckb]

I also run mobil 89 in the es. 93 once in a while if I'm feelin generous :D

the 430 gets mobil 93 everytime.

[mugwai]

My manual says to use premium, but a friend said I could use regular unleaded without any problems. 

Anybody have any bad experiences with regular unleaded gas?

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there is no point these are not race car's and the compression ranges we run nowdays high octain gas is a wast and u will see no diffrence in carbon bildup on car's running reg or high oct if you were to pull the top end off the differenc would be from the amount o highway mils and the amount of water in the fule u run. if you were to have a v8 or a turbo then u would need the high octan like in my big block 440 i hav to run 97 oct to make it run with the compression i have but that is a racer bilt for high performanc.\

[hankn]

From the many past comments on premium or regular fuel use, many said the difference has not been observed.

Premium fuel has higher octane AND I assume in US, it also has cleaning agent in as well, eg in Shell Optimax, BP Snergy etc.

It is possible for the following effect to take place ?

If you have been using regular fuel regularly and you switch over to premium with cleaning agent, you may not notice the immediate difference after one or two tank filling as the carbon deposit has NOT been cleaned well yet. Perhaps if, you continue after a few tankful, the difference will be observed together from the benefit of higher octane power. (assuming the car is "tuned" to cater for higher octance level? - to take advantage of higher octane)

Likewise, if you have been using premium regularly, perhaps the carbon deposit is minimal. If you siwtch over to regular, you may not notice the difference due to less carbon deposit interference. If you were to continue to use regular (without cleaning agent) or other fuel injector cleaner, perhaps the carbon will gradually begin to build up to interfere & reduce power etc.

I have personnally observed premium gas (with cleaning agent) with octane 98 giving better performance/power boost than regular after switching to & using premium for awhile. But then it could be my imagination!

Comments?

[mugwai]

From the many past comments on premium or regular fuel use, many said the difference has not been observed.

Premium fuel has higher octane AND I assume in US, it also has cleaning agent in as well, eg in Shell Optimax, BP Snergy etc.

It is possible for the following effect to take place ?

If you have been using regular fuel regularly and you switch over to premium with cleaning agent, you may not notice the immediate difference after one or two tank filling as the carbon deposit has NOT been cleaned well yet.  Perhaps if, you continue after a few tankful, the difference will be observed together from the benefit of higher octane power.  (assuming the car is "tuned" to cater for higher octance level? - to take advantage of higher octane)

Likewise, if you have been using premium regularly, perhaps the carbon deposit is minimal.  If you siwtch over to regular, you may not notice the difference due to less carbon deposit interference.  If you were to continue to use regular (without cleaning agent) or other fuel injector cleaner, perhaps the carbon will gradually begin to build up to interfere & reduce power etc.

I have personnally observed premium gas (with cleaning agent) with octane 98 giving better performance/power boost than regular after switching to & using premium for awhile.  But then it could be my imagination!

Comments?

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I dont know about the US but in canada all fuel has cleaner's diesl and gas all oct levels they also hav fuel line antifrees

[Toysrme]

1) In this car. I never run premium. You could add... 15 degrees of timing advance on any descent 87 octane after 5000rpm and not ping. 3vz-fe's are... Rediculously under-tuned. It wouldn't have a problem if you could run 80 octane fuel through it.

2) All year 1mz-fe's have extremely over-sensative knock sensors. Wether or not lexus asks for premium gas, Toyota does... I have no idea why Lexus doesn't in some of your manuals. You definately can see the timing being retarded when you run 87 octane on a dyno. Instant 5-10hp and large throttle responce lost as timing is pulled and replaced.

(A side note. Many midly modified 1mz-fe's will pull timing on 91 octane gas.)

Relocating, replacing with less sensative knock sensors, or running a stand alone are the only solution.

3) High octane gas has more additives.

During the mid-late 90's oil companies were dumbing huge amounts of cleaning agents into all of their gas. The federal government stepped in and said, "Gee, this is a great idea, we'll mandate they do it!".

Unfortanutaly the US government is retarded, and mandated many times lower the amount being adding.

For the last few years, all oil refinaries have been spitting out the same minimum quality crap they can get away with. Profit margin > being nice.

That being said:

If you have a 3vz-fe and are running 87 octane...That's just really sad.

If you have any year 1mz-fe, and can detect a slight ping, feel the engine faintly holding back, or surging. You need to run higher octane.

If you're running any engine on low octane gas, and are not experiancing timing loss, or pinging. You have no reason to run higher octane gas.

About the 1mz-fe knock sensor problem. It's horrible in 94-95, slightly better in 96, and better, but still bad 97-01. The problem itself is the exact same. The "sensative ECU logic" was toned down as the years progressed, but never "fixed" as it's not a "problem". Like I said... If you know what you're looking for it's noticeable on all of them, but make any amount of descent power from them and it's horrible.

IDK about the 3mz-fe's.

[husker]

During the past long weekend, we went on a road trip covering 500 miles (95% highway milage) round trip. My 98 ES300 gave 25mpg on highway. I just used 89 Octane gas with 10% ethenol. I haven't tested my vehicle for complete city milage yet.

[amf1932]

Being an original owner of a '91ES250, then a '94ES300, and now the current owner of an '03ES300, I can honestly say that I didn't notice ANY performance or gas mileage increase when switching to Premium fuel.

When each of these cars were new, I originally used Premium fuel for about 1 year of operation, and then switched to Regular Grade. I never heard engine knocking(pre-ignition) on any of these cars......even going up hills.

Although, I did notice my wallet was fatter.

Here is the chart taken out of my 2003 ES Owners Manual: