nopcbs

...of premium will keep the injectors cleaner longer. But so will running some Techron through the engine a couple of times a year.

http://www.chevron.com/products/prod...t/fueladd.shtm

loudmouth

I used regular. It works same as the premium.

JA Cambece

TunedRX300

I am not sure about RX330 but with RX300 if you just leave the shift at "D" the RPM will never be higher than 3000. It is a little silly to talk about performance improvement while the car is running 1000-2500 95% of the time. According to Lexus' web site, 2006 RX330 won't reach the peak 223 hp until 5,600 rpm, how many of us ever rev the engine up to 5600?

SWSC400

I use mid-grade in my SC400, works fine....most people do not buy premium and therefore it sits there and gets "heavy" only to cause more problems. Also, try to stick with a name brand like Chevron or Phillips (no Costco or Sam's Club) and pick a gas station that is busy, they get fresh fuel more often.

DaveJ

Just returned home from a 1000+ mile trip including driving through the WV mountains. This was the first test of using 87 octane instead of 91 in our RX300. I never noticed any less power or knocking, and the fuel economy seems to be the same as what we've always acheived on long highway trips (23-24 mpg). It's regular from now on in our RX300.

mmahamm

Congrats on all the money you will save.

Benjamin T

iTrader: (2)

the lexus salesperson told me regular only and premium would just be a waste.

i usually use chevron 89. i tried 87 but the engine would ping. my mom put 94 in by accident once and i didn't see any difference in fuel economy on the computer.

BOWTIE 3

If you change from a higher octane fuel to " regular " [ 87 octane ] be sure to pull the ECM fuse for about a minute. [ It's the 7.5 amp fuse ] That will allow the computer/knock-sensor to recognize the fuel in the tank at the moment. Once in a while my wife's 2000 RX300 gets a bit of a gas knock; pulling the fuse for about a minute completely eliminates that problem. Removing one of the battery cables does the same thing, but then you have to reset the clock, radio, etc.

3000

I don't have a RX but when it comes to gasoline I always get premium and octane boosters+... Usually I get shell V-power gasoline and I use stp and/or prestone boosters.

DaveJ

Thanks. I haven't noticed any knocking since switching to 87, but I'll keep your solution in mind.

bizzy928

I honestly don't know why there is so much debate. The best thing to do is follow the owners manual. For the rx300 it says the engine is best designed for 87. (Use 91/94 once in a while for the detergents to clean out your system if you wish)

LiLS

iTrader: (7)

wow good thread, i just got a 99 gs300 as a first car and the guy before me used premium but its pretty expensive nad im in high school with no job, well a temp on and off job and only make 35 bucks so theres no way i can afford gas, so theres no difference if i downgrade?

DakotaRX

When I purchased my 05 RX330 one of the first things I asked the salesperson is what gas to use. According to him, regular is just fine. He said almost all of the salespeople with RX's use regular. Also verified that when reading the owner's manual. My previous Lexus was a 98 GS300 which was definately a premium burner. I have used the mid-grade a couple times during really cold weather due to the ethenol absorbing "water" in the tank. Yes, there is a slight decline in gas mileage with it due to the "thermal units" of ethenol being lower than gas. Also you may even notice the vehicle will run just a little cooler as again due to the ethenol having less thermal units so it doesn't run as hot as regular gas. Even the leading consumer magazine states that 98% of all vehicles on the highway run on regular and running anything else in them is a waste. You will only notice better acceleration with higher octane, usually not increased mpg. I have also notice that here in ND regular gas is 87 octane, mid is 89 and premium is 91 or 92 but in my travels thru Montana and Idaho (2 or 3 times a year), their regular is 85, mid is 87 and premium is 89. I believe that has something to do with the altitude. But it really boils down to use whatever you want, running regular is fine for it but if you want to run higher octane it isn't going to hurt it (only your pocketbook).

jfelbab

I can also confirm that ethanol reduces my gas mileage. This is especially obvious in the winter blends required in some areas of the country. Just completed a 1,500 mile trip where I got 26.8 mpg on non-ethinol based gas vs. 25.6 on ethanol based gas. This was an my RX 330 AWD at 68-72 mph. I have verified this repeatedly as I make this trip a lot.

Maybe the exhaust gases are cleaner but the mileage is less so I have to burn more of it. Perhaps this ethanol product is in the gas to reduce foreign oil dependance. Or maybe it is due to intense lobbying efforts by the farm states. At least it isn't the fiasco that MBTE turned out to be. Evidence of our fine EPA at work.

LexFather

Premium. And after reading an article in CAR, it will be BP Ultimate