Spark Plugs
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Driver
Joined: Apr 2023
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From: Virginia
NOTE: There are many videos on YouTube regarding maintenance and service items for the ES350 engine, but many times it will be under Toyota Camry or 2GR-FE engine. The V6 Camry and ES350 are basically twins under the hood. One of the best YouTube channels for Lexus repairs is The Car Care Nut.
What is your MPG?
If you are in an area that has winter blend and summer blend fuels, you should see a slight increase in mpg as gasoline switches from winter blend to summer blend on May 1st
During the summer, I get 31-32 mpg on long interstate trips when driving sensibly and using PREMIUM fuel.
In my normal day to day driving which is about 60/40 highway/city and using 87 octane fuel, I get about 24 mpg during the winter and 26.5 mpg during the summer. I might expect 20-22 mpg in all city driving, but that is just a guess.
As mentioned before, your driving habits (acceleration and braking), highway vs city, and tire pressure will have a huge effect on your fuel mileage.
What is your MPG?
If you are in an area that has winter blend and summer blend fuels, you should see a slight increase in mpg as gasoline switches from winter blend to summer blend on May 1st
During the summer, I get 31-32 mpg on long interstate trips when driving sensibly and using PREMIUM fuel.
In my normal day to day driving which is about 60/40 highway/city and using 87 octane fuel, I get about 24 mpg during the winter and 26.5 mpg during the summer. I might expect 20-22 mpg in all city driving, but that is just a guess.
As mentioned before, your driving habits (acceleration and braking), highway vs city, and tire pressure will have a huge effect on your fuel mileage.
I only get 10.5 mpg combined hiway/city driving! I do 90% city driving. My tire pressure is about 36 psi all tires, I don't have a lead foot! I bought new plugs, not installed them yet! I thought we had to always use premium fuel? Isn't 87 Octane bad for engine?
Pit Crew
Joined: Dec 2020
Posts: 151
Likes: 36
From: Illinois
10.5 mpg does sound awfully low, unless you are letting it idle a lot without moving. Remember, whenever your car is idling but not moving. You are getting 0 MPG.
Spark Plugs: Where did you buy them? If you bought your spark plugs on eBay or Amazon or Facebook, throw them away or send them back. Most of them are fakes. Only by your spark plugs from an auto supply store or RockAuto.
87 Octane gasoline: your car will run fine on 87 octane gasoline. You will see a slight decrease in fuel mileage and your engine will not produce the advertised horsepower, but it otherwise should not create any issues. My engine has 227,000 miles on it and still doing well, and I almost always use 87 octane except for a couple of times a year when I'll run premium fuel for a long trip.
You may want to take it to a reputable shop and have them check it out. They should be able to diagnose if you are having issues with the oxygen sensors or some other component (MAF Sensor, Fuel Filter, etc).
Caution: If you decide to clean your MAF, unhook your battery first.
A very dirty fuel filter can lead to low fuel pressure, so that might be an issue. As I mentioned before, sometimes throwing the parts cannon at it will cost you more than taking it to a good shop for diagnosis.
Spark Plugs: Where did you buy them? If you bought your spark plugs on eBay or Amazon or Facebook, throw them away or send them back. Most of them are fakes. Only by your spark plugs from an auto supply store or RockAuto.
87 Octane gasoline: your car will run fine on 87 octane gasoline. You will see a slight decrease in fuel mileage and your engine will not produce the advertised horsepower, but it otherwise should not create any issues. My engine has 227,000 miles on it and still doing well, and I almost always use 87 octane except for a couple of times a year when I'll run premium fuel for a long trip.
You may want to take it to a reputable shop and have them check it out. They should be able to diagnose if you are having issues with the oxygen sensors or some other component (MAF Sensor, Fuel Filter, etc).
Caution: If you decide to clean your MAF, unhook your battery first.
A very dirty fuel filter can lead to low fuel pressure, so that might be an issue. As I mentioned before, sometimes throwing the parts cannon at it will cost you more than taking it to a good shop for diagnosis.
CL Community Team
Joined: May 2005
Posts: 7,136
Likes: 1,706
From: VA
FYI replacing the rear spark plugs is not easy. You have to remove the intake manifold and or the wiper motors etc, and some coolant.
Watch some youtube videos. Also be prepared to possibly damage some coil wires or coils in the process as they can be fragile. It may be worthwhile to replace the 3 rear coils along with the spark plugs as it is so difficult to get back there that you don't want to do it twice to repair errors or unexpected damage!
However, I doubt spark plugs are your issue. You need a shop to run diagnostics before throwing parts at it as it could be a number of different things.
It could be as simple as a clogged air filter which you said you have not looked at. It only takes a minute to check and change it.
I would get a bottle of Techron Fuel System Cleaner and add it to the gas tank. It will gradually clean the fuel injectors and remove some carbon from the intake system as you drive and may help improve mileage. Get the larger sized bottle. Most auto parts stores have it in stock, often on sale.
If you are in Northern Virginia, say Fairfax County, I could recommend an independent repair shop or 2 to check out your car.
Watch some youtube videos. Also be prepared to possibly damage some coil wires or coils in the process as they can be fragile. It may be worthwhile to replace the 3 rear coils along with the spark plugs as it is so difficult to get back there that you don't want to do it twice to repair errors or unexpected damage!
However, I doubt spark plugs are your issue. You need a shop to run diagnostics before throwing parts at it as it could be a number of different things.
It could be as simple as a clogged air filter which you said you have not looked at. It only takes a minute to check and change it.
I would get a bottle of Techron Fuel System Cleaner and add it to the gas tank. It will gradually clean the fuel injectors and remove some carbon from the intake system as you drive and may help improve mileage. Get the larger sized bottle. Most auto parts stores have it in stock, often on sale.
If you are in Northern Virginia, say Fairfax County, I could recommend an independent repair shop or 2 to check out your car.
Last edited by Clutchless; Apr 27, 2023 at 05:53 AM.
Thread Starter
Driver
Joined: Apr 2023
Posts: 59
Likes: 0
From: Virginia
FYI replacing the rear spark plugs is not easy. You have to remove the intake manifold and or the wiper motors etc, and some coolant.
Watch some youtube videos. Also be prepared to possibly damage some coil wires or coils in the process as they can be fragile. It may be worthwhile to replace the 3 rear coils along with the spark plugs as it is so difficult to get back there that you don't want to do it twice to repair errors or unexpected damage!
However, I doubt spark plugs are your issue. You need a shop to run diagnostics before throwing parts at it as it could be a number of different things.
It could be as simple as a clogged air filter which you said you have not looked at. It only takes a minute to check and change it.
https://www.youtube.com/watch?v=-ibt77FrjAM
I would get a bottle of Techron Fuel System Cleaner and add it to the gas tank. It will gradually clean the fuel injectors and remove some carbon from the intake system as you drive and may help improve mileage. Get the larger sized bottle. Most auto parts stores have it in stock, often on sale.
If you are in Northern Virginia, say Fairfax County, I could recommend an independent repair shop or 2 to check out your car.
Watch some youtube videos. Also be prepared to possibly damage some coil wires or coils in the process as they can be fragile. It may be worthwhile to replace the 3 rear coils along with the spark plugs as it is so difficult to get back there that you don't want to do it twice to repair errors or unexpected damage!
However, I doubt spark plugs are your issue. You need a shop to run diagnostics before throwing parts at it as it could be a number of different things.
It could be as simple as a clogged air filter which you said you have not looked at. It only takes a minute to check and change it.
https://www.youtube.com/watch?v=-ibt77FrjAM
I would get a bottle of Techron Fuel System Cleaner and add it to the gas tank. It will gradually clean the fuel injectors and remove some carbon from the intake system as you drive and may help improve mileage. Get the larger sized bottle. Most auto parts stores have it in stock, often on sale.
If you are in Northern Virginia, say Fairfax County, I could recommend an independent repair shop or 2 to check out your car.
Why does manual and dealer only say put premium fuel in it? I don't need to lose any more mpg so will stick with premium for now!
I'm only getting around 11.2 mpg now
Pit Crew
Joined: Dec 2020
Posts: 151
Likes: 36
From: Illinois
If you do the math, you will spend less money on fuel to go 1,000 miles using 87 octane vs premium, even with the drop in MPG.
Around me 87 octane is $4/gal, and 92 octane is $5/gal. I'll be generous and say you'll lose 10 percent in MPG using 87 octane, but it isn't that much.
If I get 30 mpg using premium, I'll use 33.33 gallons to go 1,000 miles, which would cost me $166.65.
If I get 27 mpg using 87 octane, I'll use 37.04 gallons to go 1,000 miles, which would cost me $148.16.
That means that over the 227,000 mile life of my car I would have spent $37,833.33 using premium and $33,629.63 using 87 octane to go the same distance.
Math is how mankind got to the moon, and it is also how you figure out that you might save money even when your MPG goes down. If both fuels cost the same per gallon, obviously using premium would pay.
Last edited by sthpawil; Apr 29, 2023 at 12:58 PM.
CL Community Team
Joined: May 2005
Posts: 7,136
Likes: 1,706
From: VA
Lexus only says to use Premium fuel so they can claim that the ES350 has a more powerful engine than the Toyota Camry which runs on regular fuel. It is the exact same engine, but when you use premium it develops 5 more horsepower. The knock sensors take care of controlling the engine (these have been used for 30 years and are old tech) to protect it when using different fuels. So you are wasting money on premium. You will probably never notice the difference when driving.
My niece has had my mother's old 2010 ES350 for 5 years and always uses regular gas. It has over 100,000 miles and runs great, getting mileage in the 20s.
Whatever the problem is with your car, running premium will not fix it. You need to get the engine thoroughly checked out by an honest independent skilled mechanic.
I may have found a great Richmond shop for you. Take it to Ironwood Automotive. They are an independent Toyota/Lexus/Honda/Acura specialist shop with 5 star Google ratings.
https://ironwoodautomotive.com/
My niece has had my mother's old 2010 ES350 for 5 years and always uses regular gas. It has over 100,000 miles and runs great, getting mileage in the 20s.
Whatever the problem is with your car, running premium will not fix it. You need to get the engine thoroughly checked out by an honest independent skilled mechanic.
I may have found a great Richmond shop for you. Take it to Ironwood Automotive. They are an independent Toyota/Lexus/Honda/Acura specialist shop with 5 star Google ratings.
https://ironwoodautomotive.com/
Last edited by Clutchless; Apr 28, 2023 at 05:57 AM.
Thread Starter
Driver
Joined: Apr 2023
Posts: 59
Likes: 0
From: Virginia
Lexus only says to use Premium fuel so they can claim that the ES350 has a more powerful engine than the Toyota Camry which runs on regular fuel. It is the exact same engine, but when you use premium it develops 5 more horsepower. The knock sensors take care of controlling the engine (these have been used for 30 years and are old tech) to protect it when using different fuels. So you are wasting money on premium. You will probably never notice the difference when driving.
My niece has had my mother's old 2010 ES350 for 5 years and always uses regular gas. It has over 100,000 miles and runs great, getting mileage in the 20s.
Whatever the problem is with your car, running premium will not fix it. You need to get the engine thoroughly checked out by an honest independent skilled mechanic.
I may have found a great Richmond shop for you. Take it to Ironwood Automotive. They are an independent Toyota/Lexus/Honda/Acura specialist shop with 5 star Google ratings.
https://ironwoodautomotive.com/
My niece has had my mother's old 2010 ES350 for 5 years and always uses regular gas. It has over 100,000 miles and runs great, getting mileage in the 20s.
Whatever the problem is with your car, running premium will not fix it. You need to get the engine thoroughly checked out by an honest independent skilled mechanic.
I may have found a great Richmond shop for you. Take it to Ironwood Automotive. They are an independent Toyota/Lexus/Honda/Acura specialist shop with 5 star Google ratings.
https://ironwoodautomotive.com/
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