squarehat

I'm with amf1932, the owner's manual for my '96 simply says 87 or higher. Stefwilli, your brother's GS has a different engine, of course, and it says right on the gas gauge "Premium Unleaded Only."

beab951

If the car doesn't knock, the octane level is OK. Higher octane doesn't mean higher performance, it just is more knock resistant. I run a car that has a modified Tubo engine and I have to be very carefull when I turn up the boost to increase the octane to the correct level or the knock will blow the head gasket, or worse rings, pistons etc.


Check out this link from the FTC.

http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

steviej

iTrader: (1)

Alan, I understand totally what you are saying and posting. I have seen your copy of the owner's manual. You don't seem to understand what I am saying. The 2002 ES300 manual shows the opposite of the 2003 manual.

It states,and I quote
"Select premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher for optimum engine performance. However, if such premium type cannot be obtained, you may temporarily use unleaded gasoline with an Octane Rating as low as 87 (Research Octane number 91)."

I will scan, fax, post or email you a copy of the fuel requirements from the 2002 manual if you desire.
We have hashed through this before.

It appears that Lexus has flip flopped their octane recommendations several times.

steviej


ps, I think regular (leaded) gas is only available to race tracks now.

Lex3486

Easy guys; jeez Keep in mind that my car, which IS the topic of THIS post, is a 93; COMPLETELY different engine, thus different specs..That's a good suggestion there Stefwilli; I thought the same thing myself, until tonight. I finshed off that tank that it was on when it was actin up, and filled it up again with 93 octane rating fuel along with a bottle of Chevron Techron fuel system cleaner (used a little under 12 gallons, the maximum suggested amount) but the car still did this a few times tonight. This is a really peculiar problem b/c half the time, the car accelerates smooth as silk, almost as if brand new. Heck, you can even bark the tires off the line! The other half, however, it either scares the life outta you b/c it decides to hesitate just as you pull out onto a busy road, or it urges you to check the rearview to see if your transmission has caused any damage to the car behind you, seein how you're almost 100% positive it's just left the vehicle!! In fact, it's shifted so roughly a time or two that it seems that it's wiggled somethin deep inside the depths of the dashboard loose; it now rattles when the car shifts not so smoothly, which as I said is only probably 50% of the time, as well as when I turn my system up too loud..Although the shifting isn't the greatest, I don't think this is a transmission problem, as I did initially. I guess that whole bit is just b/c the car's got some age. I think now that it's got somethin to do with the intake system, b/c it acts almost exactly as it did once when I forgot to tighten the piping after servicing the car, or on my old ES when it developed a big ole' crack. AND BEFORE ANYONE SAYS THIS, I of course have checked to see if it's tight and if there's any obvious damage to the pipe. I don't know; I've got tomorrow off, so maybe I'll go pokin around on it some..but if anyone has any more suggestions that haven't already been brought to the table, or better yet, personal experience similar to mine, I'd love to hear from you! I hate it when my baby's not well

Toysrme

amf I state it from personal experiance with THIS '93 and some GM vehicles that simply do not like some grades of gas (or got a few bad tanks in a row).

The simple fact is if I don't run some fuel additive, or higher grade gas every once and awhile, the engine looses all of it's power. I'm guessing b/c the ECU dosen't adjust properly...

It happens on many cars for whatever reason; car makers set aside.