gabzor

i run 89, i seem to lose power in 87.. 89 and 91 i can't tell a diff besides going uphill a little.

davensd

The car will run on 87, but with reduced power since the computer will take in the octane into account and adjust the fuel/air mixture.
You do need 91 for proper operation.

Dave

Sunyata7

Never thought of the ES300 as a car that would need higher octane fuel. I've had my 97 Lexus for 2.5 years, and just realized last week I'd been pumping 85 into it when it recommended 87 (I had been having knock sensor issues, although I don't think my car knocks).

have I ruined my car?

Mxkmster

pinging canbe from heat build up because of carbon. If you run detergent fuel that will slowly go away. Otherwise a engine tear down would be needed. I have ran 91 detergent fuel and I have noticed a big differance. There is more power that can be made with 91. When Lexus performed the engine testing it was with 91. I get 5mpg better with 91 then with 87. Also changing from the stock wheel size to 17" bumped up 2mpg

MrShim78

if you are in Canada, you should use premium from a place that does not put ethanol in premium gas.
basicaly the biggest difference, besides octane is the use of ethanol upto 10% in regular gas.
not sure about the US but here in Canada as they put in upto 10% ethanol, mileage and power suffers.
I always use 91 octane premium (either shell or loblaws or pertro canada -anything without ethanol) and compared to regular, i see a major difference in power and mileage.

Mxkmster

you can ruin a car running too low of octane but if you run 85 compared to 87 its not going to blow the engine up.

Sunyata7

Pretty sure my car is pinging. Didn't realize it was just a clicking sound. ****ing Colorado, setting "regular" at 85 when every other state sets it at 87. Been running my 97 es300 on 85 for almost 3 years. Hope I didnt hurt the engine.

Mxkmster

I would try adding some octane booster with the 85 and see how the performance changes. The easiest thing to do is try an induction cleaning, and clean the throttle plate. Then, run some top tier detergent fuel that is 91 octane. There should be a noticable change in performance. If your buying costco/arco gas that can be part of your issue too. Cheap gas doesnt have the cleaning agents in it that keep gum/ carbon build from forming. Dirt intake runners, intake valves can cause misfire and idle control faults show up. The induction cleaning can help with that if it isnt too dirty. The best thing to do is go for a full tune up that way you know whats been done.

BDSL

Please don't use octane booster. It has been proven (on dyno) that they do more harm than good.

As for tune-up, spark plugs are required to be changed every 60k miles. It is not a bad idea to do a Seafoam treatment once a year or so.

285exp

I doubt you're hearing pinging. These cars have knock sensors, and the purpose of those is to prevent knock by retarding the timing when they detect detonation. If the knock sensors fail the computer defaults to retarded timing, so at worst you should have slightly reduced fuel economy and power. In any case, if it's been running on it for 3 years and you haven't had any damage yet you're probably pretty safe.

youngim87

Before I get flamed for posting an already discussed topic on here I want to let you know I did about 2 hours of researching on CL and still cannot make a conclusion on what I was trying to figure out.

So, I proceed with my question: Background info - I recently bought a used, but excellent condition, 2002 ES300 with 73K miles which was driven very lightly by the 1st owner mostly for a work commute. It was driven by a woman in her 60's so I highly doubt it was driven hard and long on a daily basis. I was informed that only 87 (regular) octane gas was used as well as regular motor oil (non-synthetic). The driver's manual calls for the use of 91 octane and I have read on here that the use of lower octane, more specifically 87, would most likely cause some type of knock/pinging due to the faster burning lower octane gas which retards the engine response to the fuel quite a bit. This particular car doesn't seem to have any type of noticeable engine problems, pings, or knocks and drives very smoothly, however, I have only had the car for 3 days so far so who knows what I'll encounter *knock on wood*

My question is: Should I continue to use 87 octane gas or should I switch over to 91 octane gas for the first time in the car's life? I'd much rather put 87 to save a couple bucks at the pump and remain consistent with the previous owner. Any suggestions or experiences would be appreciated (Sorry if that was a long post )

hypervish

The 2002 manual states
Link to 02' ES300 manual:http://drivers.lexus.com/t3Portal/do...pdf/sec6-2.pdf

The 1MZ-FE motor is high compression coming in at 10.5:1, meaning it will take advantage of high octane fuel.

You bought a Lexus! Don't try to save a few cents now.

PuReChaos

I had a similar situation to you, I bought my 2003 ES300 off my grandmother. She had always filled it up with 87. However, when I got the car I noticed nothing and the car ran smoothly. I decided after reading a few listings on CL that I would make the change to 91 and upon the first fill up, my milage dropped significantly. It went from being ~330mi to 280mi per tank (just using the cars milage estimator). It took a few tanks to finally get my car back up to around 330 but I have noticed the car preforming better on the highway.

But unfortunately I live in San Francisco, so there is very little improvement on city driving and it pains me to fill up 91 when it does no better than 87. With all this said, I don't regret making the switch as I drive to 1 hour highway to work. But just adding some details about when I made the switch.

The topic has been heavily discussed on here and you'll get people saying things for both sides of the argument.

BDSL

There are too many variables:
- condition of the engine
- the climate
- acceleration / load driver exert on the engine
- the ability of knock sensor to retard the ignition timing
- traffic condition
- etc.

What works for one vehicle/driver might not work for other vehicle/driver.

Therefore, if you are knowledgeable driver and can take some small calculated risk then use 87 octane.

If you are not a knowledgeable driver, stick with 91 octane. Don't be a hero.

youngim87

GREAT RESPONSES! Thanks for the feed back!!!

How many miles did the car have when you bought it? I know you said you got better performance on the HWY with 91, but did you notice any changes in your city MPG, or noticeable HP gains overall from 91? Also, did you happen to ever get over the 330 threshold with 91 octane? Thanks for your informative story, this was the type of response I was hoping for