Didn't get a chance to update everyone but I did end up getting a 2016 ES350 with all your help and advice! Thank you!! I really think all of you are more knowledgeable than some of the dealership salesmen! One tells me I have to use Premium on this car?! I thought all of you said unleaded but Question for all of you is do you recommend 87 or 89? Appreciate all the experts chiming in thanks!

 

There is absolutely no reason, with the Generation 6 ES, to use any fuel other than regular 87 octane fuel. With a compression ratio of 10.8:1, using higher octane is not going to improve either performance or fuel economy. And, with variable valve timing, issues with engine knocking should be non-existent. Some earlier versions of the 3.5 liter V6 that has been used by Toyota/Lexus for a number of years, premium fuel was "recommended", but the only reason for that recommendation was that, with the EPA regulations at the time, Lexus/Toyota could qualify for a higher EPA emissions rating with a recommendation for premium fuel, but the cars actually performed just as well and had no loss of fuel economy with 87 octane fuel.

 

Thank you! That is exactly why I'm asking on this forum., some have told me 89 because of the claim of increased fuel economy

 

QUOTE=prosgal73;9573385]Thank you! That is exactly why I'm asking on this forum., some have told me 89 because of the claim of increased fuel economy[/QUOTE]

I agree with lesz. Since the 2011 or 2012 model year, regular unleaded has been recommended for the ES350 and there is really no need or benefit to using higher octane. RX, Camry, Avalon, Highlander, Sienna etc. all use the same engine with regular recommended. Enjoy the new car.

 

I only have a little over 4000 miles on mine, but have tried some higher octane gas to see whether it affected the mileage. I didn't see any improvement in either mileage or the way my car runs. I am sticking to Top Tier gas, which contain additional detergents to reduce the amount of carbon deposits. So far, I've been filling up at Costco, Chevron, and Shell. Here is a list of the Top Tier retailers: http://www.toptiergas.com/retailers/

 

Thanks everyone!

 

Like Jim said, I would stay with Top-tier gas. Your car is still new... so few years later, I would use chevron complete fuel system cleaner in the gas once or twice a year. I recently read that a major car company high level executive uses chevron fuel system cleaner in his car

 

The Shell station is near me so I was going to use their Regular Unleaded sound good? Sorry to sound ignorant but how is that system cleaner used?

 

You just put it in your gas tank (amzon link below). Again, don't need it on a new car... can use few years down the road
https://www.amazon.com/Chevron-65740.../dp/B00092893E

 

This is just as widely debated as oil change interval. I personally always used 87 octane and there is absolutely no reason to go any higher. But you'll see people who swear by premium fuel and their supposed boost in fuel economy and power.

 

87 regular is fine. Premium fuel shows the most advantage in turbo engines.

 

87 Unleaded is what you should use. Anything more will be de-tuned by the ECU and will be wasted. There's been a lot of studies on this and there discussions/research on YouTube. Some even conclude that you will get worst mpg by using premium fuel on a vehicle where it is not necessary.

 

I'm actually surprised that, in the replies to this thread so far, no one has yet chimed in with erroneous advice and claimed that you will get better mpg or performance by using premium fuel in a car that doesn't require it.

 

Don't give anyone ideas.

 

The engine on my GX has a 10:1 compression ratio. In the manual, it says that 91 octane fuel is recommended but that using 87 octane fuel is satisfactory. As I said in my earlier post, the only reason for the "91 octane recommendation" was that, with the EPA standards at the time, Lexus could get a better emissions rating by recommending 91 octane fuel. When the EPA standards changed a couple of years later, Lexus started recommending 87 octane fuel for vehicles with the exact same engine. Yet, whenever this topic comes up on the GX forum, there will be numerous posts from people insisting that, if you don't use 91 octane fuel in that vehicle, you are going to do irreparable damage to the engine, have engine knocking, have diminished fuel economy, etc. I've been using 87 octane fuel in mine for 11 years. I've never heard a single engine knock, my engine hasn't fallen apart, and my fuel economy has consistently exceeded the EPA rating for the vehicle.