I pumped premium gas

 

This site describes the new standards of which Toyota is one of the founders as well as approved retailers with "superior" additives etc.
http://www.toptiergas.com/retailers.html

 

What do you use in LS 400 1990? dOES ANY ONE KNOW WHAT WILL HAPPEN IF YOU USE REGULAR?wILL IT MESS UP YOUR CAR?

 

I have been driving a different car to work (a Dodge Caravan) while my uncle does some minor aesthetic work on my car. In Mexico, we have a 92 octane low sulfur (if you can call it low sulfur being 5 times the max in the U.S.) and an a 87 octane high sulfur. I have tried with the Caravan(after I put in a K&N filter, synthetic fluids, adjusted tire pressure, basically a tune up) both the premium and the regular (which we call Magna). The Magna is pure crap and it drives like it, but it will not hurt the vehicle.

However, one note of caution is that I know from my experience and that of my uncle and others (and may be much more true down here) is that if you put in premium after using regular for a long time, the car will have some detonation issues and will not perform right at all. However, if you use the premium and then go to regular, you probably will not notice much but some sluggish performance.

U.S. gas is by far superior in quality and when I read that many of you do not feel and difference going down to regular or plus from premium except for a fatter wallet, I would not doub that, but in Mexico it is quite a different story.

 

Someone posted that regular 87 octane is just fine!

I second that!

I'm one of the persons who has an alternate vehicle which required premium fuel and when I purchased the RX, decided fuel price wasn't a factor and therefore used premium for about 1 year.. UNTIL, one of the CL members indicated the reason my trani wasn't shifting smoooooth as butter might be from higher octane than is necessary...

Well what do you know... since I switched to midgrade and regular trani shifts like a Lexus should.

Therefore in my opinion it sure seams like the rx300 was designed for regular 87 octane.

my $.02

 

what brand of 87? our 00 rx300 knocks on 87-anything... dealer said to go up to 89 and the knocking has stopped

 

I used premium gas but my 2000 RX 300 AWD only run maximum Hghwy
15.7 miles per gallon. How do i get more miles ?

 

Hmm... i'm running whatever Costco has in their tanks at 87 octane and it runs great. I average 20mpg between city and hwy driving.

 

I use Premium whenever it is around the x < 2.65 range. When its higher than that, then i used midgrade, but i never go lower than midgrade.

 

Local dealer told me that it uses Premium. That Regular will mess up the car.

OF course, since I bought the RX used, I have NONE of the users manuals.

Any idea where to ge the 1999 manuals?

 

I find that very hard to believe that "regular" gas will mess up the car. The car will run just fine on regular gas. Premium fuel is NOT a requirement at least not the the 1999 models. Whether or not the car will run more efficiently with premium fuel is another debate.

 

I believe you can access the manuals on the Lexus Website. I think you might have to register to gain access.

 

troll the ebay auctions... i've seen manuals come up on occasion.

 

Actually, it will mess up your car.

My husband traded cars with me (an Altima for a Lexus, I obviously got the better end of the deal). He told me that I had to put at least midgrade gas in or it would not work. I didn't believe him. I put regular gas in. The first time, it worked. The second time it did not. I was pulling out of the gas station and the car turned off. I cranked it up and it went a few more feet and stalled again. I had to gun the gas to get it to go. I was terrified that something was very wrong with it. I immediately put midgrade gas in it and it worked fine. Another time I got some "bad" fuel. It was from a kind of shady gas station and once again, the car stalled and I had to put better gas in it. There's nothing wrong with the car, though. I called the dealer and they said that that is what happens if you put the wrong gas in it. It really ruins your day when your car won't go for no reason, and I'm not really sure what the long-term effects are, but it definitely WILL mess up your car if you do it long enough (or at least it did to mine).

As far as premium gas goes, I conducted a little experiment for myself. My RX300 has a digital gauge that tells you how much gas mileage your car is getting. It was stuck at 19.4 mpg when I used mid-grade, so I started using premium for a couple of months and it has shot up to 21 mpg, so it definitely does help. If you do the math it's really only about $1.50 more expensive to get premium. Therefore, for every dollar you spend using premium gas your car will go roughly 9.72 miles. For every dollar spent using midgrade gas it will go 9.70 miles. So premium is a LITTLE bit better. Very small bit. But that's enough math for today. And someone might want to check me on that, because math wasn't my best subject. That's figuring with a 15 gal tank, which isn't EXACTLY what an RX300 has, but it's pretty close.

 

Has anyone tried to dyno the car using different gas grades? I remembered reading an article in a car magazine (maybe Car & Driver) a few years back where they tested different cars by using regular and premium gas. Cars that were designed for 87 gas have higher horsepower using 87 gas, and like wise for 92 gas. I only remember a few among all the cars tested and they were Honda Accord, Toyota Camry. The article also showed dyno graphs for each car.