lexus114

Very good point RX330inFL! However even on my original equipment Michelin's also "V" speed rated. I got around the same mpg`s. And these Cooper`s have been very good tires. better ride, better handling, better snow traction. much better than the Michelin`s ever were.

kickin8

iTrader: (1)

better grip means you need more power to roll?

more power to roll = lower mpg?

I honestly think it's the winter blend fuel that causes the lower-than-normal mpg....

RX330inFL

Was just another component in the equation on the topic of poor gas mileage which crossed my mind as I was looking at my own tire situation. Sure, the current gas has a lot to do with it. But a number of other smaller items, such as tire choice, can also add up to make things worse. Wondering how your MPG would be with a different tire choice, such as the Bridgestone Ecopia or other low rolling resistance tire?

As I was reviewing tire availability and pricing it occurred to me that I should (or may have to) purchase five tires this time around instead of four. I looked at the pricing listed for the Cooper CS4 Touring and it being some $40+ a piece cheaper than other tires such as those from Bridgestone. So, all this seemed to blend into my cross-posting on these two topics. If I have to replace all five tires I have to calculate to see if it would be more cost effective for me to go with the Cooper tires to save money or to get something which might give me an extra MPG or two per gallon of gas. Of course, I have other criteria I need to consider so it is not a cut and dry decision. The fact that no one has stock in the CS4 at the moment may make the need of choice moot unless I decide to wait until I really must have new tires.

hypervish

Tires can have a big impact on mpg, my General Grabber HTS tires on my RX300 have decreased by mpg by nearly 10%. I can directly relate it to the tires.

jfelbab

Some of the mpg lost is likely due to the change in tire circumference of a new vs. worn tire. Even if you change from/to the same tire brand and size tire, a new tire will usually appear to give you less mpg than the worn tire.

Another contributing factor is that a new tire has more tread squirm and higher rolling resistance than a worn tire, as much as 20% higher according to tirerack.com.

lexus114

Yeah I agree with the winter blend fuel being most of the culprit.

tromly

good catch, I was wondering the same thing.

nsexton

Did your check engine light come on? mine did and they replaced the mass air flow sensor and my mileage went from 17-18 to now 7-8 and won't shift into overdrive

lexus114

Make sure the connection is good.

ausbun

I own a 2003 SC 430 along with my wife's 2007 RX 350, and I started getting better mileage on it when I simply cleaned the mass air flow meter. It took about 30 minutes, mostly checking my computer screen to make sure I wasn't missing anything in the online instructions. I used a screwdriver and an aerosol can of MAF cleaner I bought at the local car-parts store. I'm not sure if the cleaning process is the same for the RX, but I bet some mechanic on this forum does. (There might also be some differences in the RX 330 and the 350 engines that I'm not familiar with.)

RX330inFL

I do not believe we have an official write up of this for the 2nd Generation RX. Hey, alchemist... do you want to take this one on?

Briand_OH

Just a FYI:

Recent Grass Roots Motorsports magazine did test on rolling resistance for some performance tires.

pablo87

I also was getting poor fuel economy, tried everything (premium, seafoam, change plugs, clean maf, clean tb, etc...). Recently put a can (150ml) of liquid moly (lubro moly) valve clean (ventil sauber) in the gas, all of a sudden better fuel economy (25mpg 40mph (60-65 or 15-20) 6 hour trip) and more power on 87 gas from Costco. $6 at napa. YMMV!

1koolfella

iTrader: (1)

I've seen that some of the MAF cleaners do not work with Lexus vehicles.

HokieCJ7

If you are reading the side of the bottle, that's old news and doesn't apply to our current or future types of MAF sensors.