smokesgtp

The fact you would retard the timing on a 1993 ES300 really kind of solidifies why no one listens to you, and the name calling isn't necessary. How old are you honestly? So you purposefully made the car slower and less efficient so you feel you could run on 87? Does it idle like a mack truck? I already know the answer. Unless your going turbo, which would make you the fin moron because you drive an ES, why would you do that, even then it doesn't make sense? The manual says 87 is all that is necessary on my 3rd gen. Try reading it. It mentions nothing of it's use when better gas isn't available. It just says 89 or 91 octane may be used "for increased performance." We drive V-6 camrys with more sound deadening material, much sharper body lines, and nicer seats. The compression ratio is not astoundingly high what is it 10.5:1?, you can take advantage of the premium if you wish, but it's not going to hurt it one bit running regular. My car has been running regular for 90k and it sounds the same as it did at 50, Original densos still in the valve covers, soon to be changed, idles like velvet either way, i've never heard a knock under any circumstances and I drive very hard in 90% city, never so much as a check engine light. Why isn't my engine ruined? Seems like all the predetonation would have killed the engine by now doesn't it? At least fouled my plugs, o2 sensors or caused an evaporative emissions related problem? It doesn't burn a drop of Mobil One EP in 5k intervals, I don't get it.

llcoolpass

Your car is a piece of old crap like mine[but we're reducing our carbon footprint far more than if we bough a new car], so theoretically, it wouldn't matter, but the people with like-new cars 2002 - 2007 would even show the page in the owners manual where it says the engine will perform best [last long, deliver highest MPG, etc etc] if run on the premium fuel available in that area, which at sea level is 91 or higher octane rating.
Because not all gasoline is to specifications, even fuel branded as meeting the requirements may still cause some light detonation that is accommodated. Imagine, if you start off with the stuff that is rated lower and its even much lower in reality, for example 87 that is actually 85. In New Jersey, the recent survey revealed hundreds of stations were selling sub-par gasoline.
These effects are probably what ills many people like fiorininc
who said:

While the handbook for my 98 ES 300 says it is Ok to use 87 grade, the last time I tried to go that route I got nothing but trouble--knocking, lurching, choking, you name it. Then when I got it to the shop, the repairman said the cheap grade fuel had fouled the plugs, and I ended up replacing them (not cheap).
Ever since then I've used 93 grade, mostly Hess, sometimes Shell, always $$$$$, but worth it. Engine has 204,000 miles one it, fixed two valves in December, getting about 25 MPG.
Love My Lexus!

My engine, by the way, runs great, but I try to alternate a bit with regular and premium. The cheaper gas stations' premium, the more expensive stations' regular. My spark plugs are Iridium, my entire engine is completely tuned up and up to date on its maintenance, so it's possible people with poorly maintained engines even with the timing retarded 3 degrees base idle will run poor. I am poor at the moment, so I am trying to save what I can. Interestingly enough, while I should save money by actually using premium, which would allow for higher fuel efficiency, my fuel ECONOMY is bad because of the style of driving I do that keeps the engine running rich. Premium doesn't become an issue until I'm almost home, and even then, this hasn't been an issue. On longer highway trip, good premium, always.
I don't hear knock or ping or anything either, of course, your transmission upshifts when under load anyway, so you would have a much harder time getting it to happen than i would, though, I often drive in 5th gear at 28/29 mph + without the engine communicating that it's pissed off

Luckyboy

I put 91 Octane in my 1992 ES 300 (manual shift). I get 24 miles to the gallon combined Why/City driving. Is that good?

Luckyboy

I have a 1992 5-speed stick shift Lexus ES 300. Manual shift was available only in years 1992 and 1993. After that it was dropped. I have been using 91 Octane (premiun) in CA and Mobile 1 as oil. I get 24/miles to the gallon. I use Premium for the following reasons: 1) The car can pick up from as low at 15 mph in 5th gear which means I have to depress the clutch much less number of times than if I use 87 Octane gas, 2) The manual says 87 is OK but 91 is best for "performance". I like to drive spiritedly sometimes and I love the extra power that comes on after 4000 RPM, 3) one Chevron gas pimp owner told me that Premium gas is good for the engine as it burns more completely and leaves less residue on the valves, in other words keeps the engine clean. I did try 87 Octane and the engine still purrs like a kitten but the purring sounds a little towards a growl!

amf1932

I think that what you're doing is excellent, so in my estimation you should stick to it. Also, your MPG is just about the best you can do. Enjoy.

geddymd72

I think the choice of gasoline often depends on what your experiences have been and how old the car is. If you have never had a check engine light or needed to replace knock sensors, you aren't likely to believe that premium helps. Once you do, you'll be considering premium more seriously. I seem to get about 20-30 miles more per fillup with premium. If I were driving a Ford that I expect to die in 10-12 years anyway, which they always have for me, I wouldn't bother, but with a Lexus, I want to drive that for a long time.

MrShim78

I have a 97 es300 lexus. I used to use mid grade but i switched to premium. Shell V power or anything without ethanol (I am Canadian, here we get alot of ethanol mixed in )
on average with 45 city/55 highway i get about 550 to the tank. using premium has made a real difference.
the engine is smoother andi get about 50-60 k more KM.

Power6

We have an 18.5 gal tank, I've found pushing my luck a little with the fuel light I can get down to 17 gallons to fill it.

You are claiming at 50-60 extra km, about 2 extra MPG from using premium assuming 17 gal fills.

I don't buy that, premium fuel has no more energy than the cheap stuff, it is just harder to burn. There are efficiency benefits to that from advanced ignition timing if a car is designed to use premium fuel, but not enough to cover 10% improvement in MPG.

I have no proof either way, though I am wondering if your experience is more about the difference between pure gas vs. ethanol mix, there is a sizable difference in energy content between the two, plenty of testing and evidence you will get better mileage with pure gas.

Sadly I can't test this myself, all we can get in Massachusetts is 10% ethanol blend.

ES3002002

After getting my '02 ES300. I put regular (following the manual) but then the check engine light came on. I switched to 91, the light turned off, runs smooth and not a problem since.

amf1932

The engine computer in the '02 ES300 has the ability to compensate for low octane fuels. Even my previous 1994
ES300 did this. I always started to use 91 octane fuel, then I switched to 87 without any problems whatsoever!!
Possibly, you have a very high mileage car, and there is a carbon buildup that causes your problem.