RookieRick

I have a 2007 LS 460. I bought it used and it's immaculate. It has 74,000 miles on it. My problem is I get about 15 mpg around town and 20 on a 500 mile highway trip.

I talked to the service rep today and he suggested spark plugs but I just read the plugs in the 2007 are good for 120,000 miles. The service rep was of the impression they were good for 60,000 miles.

He also stated that it's easy for me to replace the plugs. That's not what I'm reading here. Seems like a lot of stuff has to come off and then I need to wedge the engine over to remove the spark packs? Is it worth the $350 to have Lexus do it or should I just wait until cooler weather and make an afternoon of it?

johnnyg66

If you have the right tools and work on cars enough should be easy enough. I am surprised they only wanted $350. When they quoted me over 500. I doubt that will fix your milage issue. How are you determining that MPG? Last time i checked my city only was around 18. Highway for me was around 24 or so.

You might want to have a fuel system done in case the last owners didnt use good gas and change the oil too. If you have not already.

RookieRick

I calculated my gas mileage by dividing the number of miles driven by the number of gallons it takes to refill the tank. I do this every time I fill the tank. It's worked okay for me for almost 50 years.

The service manager at the dealership is the one who suggested spark plugs. I also read it on line along with other things to check that affect mileage.

I got the $350 number in this forum. Maybe that was 40 years ago. The spark plugs are $16 each or $128.

If I don't have to risk breaking things in an effort to figure out how it comes apart and I don't have to disassemble half the engine to do this, I'll replace the plugs myself. Otherwise, I guess it would make sense to have Lexus do it.

Lexus has the maintenance history of the car. The owner did all the scheduled maintenance. Same owner for the entire life of the car. I have to assume anyone who can afford to buy a $65,000 car and maintain it religiously, probably didn't have to skimp on gas. They only drove it 70,000 miles in 10 years. Oil changes every 5000 miles performed by Lexus. Even tire changes performed by Lexus.

The owner did not change the spark plugs at 60,000 miles. Unknown why. It had the rest of the 60,000 mile service done. This is another reason why we're suspecting the plugs. Last oil change was 5000 miles ago. Not sure what you mean by "have a fuel system done".

UDel

Having the dealership do the plugs is likely going to cost $500 or more, I doubt plugs would make much difference especially at only around 70K miles, the plugs should be good to 120K miles but the service manual has them changing them every 60K for some reason. Have a fuel system done was probably a injector cleaning service.

I would try a fuel injector cleaner
Overfill the tires a little
Make sure your air filters are clean
Clean your MAF sensor
Clean the throttle body.


If you see no improvement then you may want to try a professional fuel injector cleaning service or a engine cleaner you add to the oil when you are about to do a oil change, Lubro Molly makes a decent one.

RookieRick

Thanks. I'll give all that a try. and post how it turns out.

The oil gets changed Friday. I'd do the oil change myself but I'm away from home and don't have a jack and oil pan here. I'll purchase the air filters and replace them myself. Any recommendation on a good injector cleaner?

I've cleaned a MAF before but I've never cleaned a throttle body. I guess I can google it. I'm currently running 35 psi in the tires.

BTW, my first around town mpg was 13. Then I started using premium gas and it went up to 15.

One last thing. The service manager told me not to use NGK spark plugs. What spark plugs are recommended with Lexus?

Thanks to both of you for your help so far.

colfax

Hi RookieRick!,

Like you I just bought a 2007 460 with only 104K and every 5k serviced by the dealer, immaculate car
ALL of my driving is around town and i am averaging 14.8-`5.2 on three tank of gas filling to full and dividing mileage by gallons used like you did.

I think this is just fine, no complaints, isn't this car rated at 17 city so that is quite close? My just sold 97 400ls only got 11-12 city.
I did check a steady 70mph on the freeway and averaged about 26 which I thought was ok too.

wasjr

For comparative purposes, I am tracking mileage using the Fuelly app on the 70k 07 460 I bought this past October . So far my combined mileage is 22.6 with a best mpg of 28.3 (all interstate driving). This is over about 4k miles as I do not drive the car every day.

Oliver Enterprises

I have a suggestion. NONE. I would not put injector cleaner in my fuel tank. I had a buddy a long time ago that tried to get a Firebird running good and he put a lot of injector cleaner in it, and it did nothing but make it worse. He then pulled the injectors and sent them to a shop for cleaning. And the shop owners said that injector cleaner was the best thing ever for his business! Because people add injector cleaner to a tank of gas, and the injector cleaner does what it does. Loosens up dirt and debris ... but it does it in the tank too! And then sends that on down the lines. And what doesn't clog the fuel filter, clogs the injectors. I seriously doubt you have clogged injectors (at the moment).

The original plugs are Denso FK20HBR11. If there is an NGK equivalent to that, I'd be willing to bet, the NGK's would be fine. But I would just run the Denso's cause that's what it came with.

RookieRick: I'm going to suggest that there is NOTHING wrong with your car. Driving conditions vary from here to Timbuktu. I would have to believe your driving practices and driving conditions are what yield your mpg results. If I just drive my low mileage (41k miles) LS "around town," I get substantially lower mpg than I do out on the interstate. And my "around town" is probably a lot easier driving than your "around town." Just around town I've probably seen in the 16's. I wouldn't sweat your mpg, unless it is accompanied with a rough running engine (and check engine lights). But yes, change your spark plugs just because the change schedule recommends it. And if you can DIY, more power to ya, would save you some loot, and let you pound your chest a bit when finished!

mckellyb

I just changed my plugs, 118K, I felt an occasional miss appear about 1K miles earlier.

40% city/60% highway, I get about 21.5-22.5, depending on how bad traffic is any particular week. My commute is unwavering, and I use Silvia for almost exclusively commuting.

It will return 30 MPG at 80 MPH, A/C on, if you're on flat terrain. That's the beauty of torque and really tall gearing. 80 MPH = 2K RPM

To put it another way, I consider highway range on a full tank a comfortable 600 miles.

Injector/fuel system "cleaner". Hard to beat Techron, but in a concentration at least double what is recommended. I used to use it if fuel went stale in a motorcycle.

This car is extremely sensitive to throttle input as it relates to good MPG. Remember, it's not light and the engine is not small nor weak. If you can make it shift below 2,500 in the first three gears, then shift below 2K after that, MPG will go up, guaranteed.

UDel

Redline and BG44K are considered the best, I have only used Redline, you can find it at some auto stores. I have never had a issue using a fuel injector cleaner, never heard of anyone having a issue either. I would use the standard same OEM plugs that came with the car.

Do you know if the car sat a long time before you bought it/drove it. My dad got a car that had been sitting for around 6 months or more on the lot and it got terrible gas mileage because the gas was old, when he refilled it, it got much better gas mileage.

wasjr

I have heard good things about Techron as well. I use Sea Foam in my truck that has 200k mi, both for cleaning and gas treatment as I only put about 2,000-3,000 miles per year on it. I had a similar experience to mckellyb with an outboard boat motor. It was running rough when I bought it, and was told by mechanic that before I brought it to him to shock it with double dose of sea foam and run wide open. After about five minutes started running much smoother.

While I don't believe there is definitive research that additives help, I have never had one do any harm. So I don't believe it would hurt to use either Techron or Sea Foam in your vehicle.

DerrickM

My ('15) LS only has 10k miles on it and it only gets about 15 mpg in the city. I don't think there's anything wrong with the gas mileage you're describing. Driving habits, long periods of idling, lots of short trips, etc., can all have a negative effect on fuel economy. Admittedly I have a heavy foot, but I don't think this is super far off from what the original fuel economy estimates were.

MobbinVIP

iTrader: (16)

I drive an 07 & I get only 15mpg around the city. I pretty much only do city driving. About 330-350 miles on a full tank of 91 (I only use 91)
Before I changed the spark plugs I was only getting 13mpg. I do mobile1 5w-20 every 5k
This time I will be trying 0w20, my mechanic said it should help with adding a mile or two per gallon, but we will see.
I don't recommend using fuel additives, it can be harmful to the fuel lines & rubber parts it comes into contact with. Had a bad experience with it on my LS430
Also, I noticed some gas brands make a difference, in my old GS I filled Costco vs Shell, I would get 50 more miles per tank with Shell, but one time I filled Shell in my 460 & the exhaust fumes coming out the tail pipes was a disgusting smell, so I don't use it anymore.

Oliver Enterprises

MobbinVIP - Understand the physics of what's going on with 5W-20 versus 0W-20. When your engine cranks, assuming the engine is fully cooled (cold), the oil begins to increase in viscosity. At least until it reaches the higher number (20). On the other hand, the colder it is, the more it tends to achieve the lower number. There's some cold temp (I want to say it is 0°C, so 32°F, and colder) where it should be equivalent to the lower number. I'm no oil expert, but I understand it well enough. Once you crank your engine, the oil warms fairly quickly. As the oil warms, it changes viscosity (thicker) to the higher number.

In your quote above, both are rated 20 in the higher viscosity. Since a car does NOT drive around on cold oil, the oil is going to be operating at a rating of 20 in both cases. So ... you will achieve no better mpg on 0W-20 versus 5W-20, at least not based on the oil alone. It changes viscosity to thinner (the lower number) when the oil cools off, so that it will flow more quickly up and around the engine to get the oil into all the intricate places it needs to be, as quickly as possible, when the engine is cranked (cold) after being off for a long period of time.

Cubbylex