jadu

iTrader: (42)

doesnt the heavier wheels also have a negative affect mpg?

iolmaster

iTrader: (1)

Geez, I though I would have gotten into a fight over the octane discussion, but too many of you came to my defense. Well, lets try again. You think there is a difference between the name brand and no name brand gasoline. I drive by a fuel distribution depot daily. I see Exxon, Texaco, Shell and lots of no name brand tankers going in there to pick up fuel. Do you think they all have a different straw? No, all of them get their gas from the same tank. Maybe some of them put a different additive in before it gets to the station, but I doubt it makes the kind of difference that one could tell in performance. You have very sensitive feet.

carguy07

http://pure-gas.org/

ausbun

I think in most cars, you are right; you can't tell a difference. But I can definitely tell a difference in my wife's RX300.

Gazootech

As long as your wife is driving the Rx you will only get 15mpg. Mine drives like a nascar driver, all gas and brake. Try an AFE air filter and E3 plugs.

bigvito

I run 87 octane in my 2001 RX300. By changing my driving habits my computer says the average mpg is 20.2 ( city and highway). Not bad for an all wheel drive suv.

bufferdan

We get about 17mpg strictly city with 20mph average with rx330 18's and 190k miles. Regular grade gas is what this engine is supposed to use. IDK where these people get this retarded info on using premium gas. I switch between premium and midgrade on my IS300 that recommends premium and no difference in mileage and i check every tank by dividing miles driven/gallons and it doesnt get anymore accurate than that

enchanted

Here is a cut and paste of the 2003 rx300 owners manual. It states 87 or higher octane with improved engine performance with higher octane.

GAS STATION INFORMATION

Fuel selection:
Select Octane Rating 87 (Research Octane Number 91) or
higher. For improved vehicle performance, the use of
premium unleaded gasoline with an Octane Rating 91
(Research Octane Number 96) or higher is recommended.

Fuel tank capacity:
75 L (19.8 gal., 16.5 lmp. gal.)

Engine oil:
“Toyota Genuine Motor Oil” or equivqlent
Oil grade: API grade SL “Energy–Conserving” or ILSAC
multigrade engine oil
Recommended oil viscosity: SAE 5W–30
Oil capacity: L (qt., lmp.qt.)
Drain and refill
with filter 4.7 (5.0, 4.1)
without filter 4.5 (4.8, 4.0)
See page 287 for detailed information.

Engine coolant:
Capacity: 9.0 L (9.5 qt., 7.9 lmp. qt.)
Coolant type – “Toyota Genuine Long Life Coolant” or
equivalent
With ethylene–glycol type coolant for a proper corrosion
protection of aluminum components
Do not use alcohol type antifreeze or plain water alone.
For checking the engine coolant, see page 290.

Automatic transaxle:
Fluid type – Toyota Genuine ATF Type T–IV
See page 294 for detailed information.

Tire information:
See page 299 through 306 for detailed information.

Tire pressure:
Tire size: P225/70R16 101S
cold tires
kPa (kgf/cm2 or bar, psi)
Vehicle loaded up
Vehicle load up to vehicle capacity
to 4 occupants weight
Front tires . . . . . . 210 (2.1, 30) . . . . . . 210 (2.1, 30)
Rear tires . . . . . . 210 (2.1, 30) . . . . . 210 (2.1, 30)
For sustained high speeds above 160 km/h (100 mph), in
countries where such speeds are permitted by law, add
30 kPa (0.3 kgf/cm2 or bar, 5 psi) to the front tires and
rear tires, but never exceed the maximum cold tire
pressure molded on the tire sidewal

lexus114

Here we go again!!

hypervish

Just use whatever damn octane you please... LOL hahah
There's been countless debates of this, no point of another one.

Xtom73G

The manual states 87, so that's what I use. Mine is 2000 RX300 AWD. I use it almost exclusively for daily commuter and work sites. My retirement job is security officer on power construction sites, often in the blazing desert of Arizona. Air con is almost always on AUTO, and I use engine and air sparingly on job sites, usually zero shade to park in, just brutal sun. In town I get 15.5 to 16.5 on 87 octane, no problems. If I use the air and just drive around town in normal traffic, but no job site air use, I get 17 to 18 mpg. Sitting still and running the air just sucks gas, clearly much more so than my old 99 Jeep Cherokee Sport straight six, which was totalled, causing me to buy the RX300 replacement. Now I can hear the radio at highway speed. Yeesss!

Cruiter

Like others have said, the 1st Gen RX is tuned for regular 87 octane. Mine was an 03 model. I sold it with 67,000 miles and always put in regular except for the period when there was a gas shortage. I did a full fill up with 93 and it didn't run near as smooth. The detonation point is not the same.

Now it's the opposite on my 2010 RX 450h. That one likes to bath the pistons with the expensive juice. But I'm averaging over 31 on the highway and over 32 in the city so .... My readout today is 31.4 since last fill up

imherenow

i hope ur RX is tinted (just saying).also u should tint your front ones too..its legal and mine front windows are tinted altho not as the glossy/slivery as the back or factory installed ones..but nonethelss i have noticed that i use less fan speed

C-Stone

Heavier wheels could affect it in the city with acceleration/decel being frequent. But probably not significantly.

JMG:

First, having a good tune with new spark plugs can always help the engine run more efficiently.

Second, I imagine you've read through the sticky up top "I have bad gas mileage..."? It's a good one.

A new air filter along with cleaning the MAF and IAC valve helped my gas mileage.

Early this year, I was getting pulsating when stepping on the brakes and the mileage was going down, down. So I replaced the front pads and rotors, and lubed the brake slide pins. The rotors were old, warping and dragging somewhat! So that helped increase mileage too.

Good luck with it!

Lexmex

The brake slide pins are an important one. I plan on doing that later this week along with some other maintenance.

The other one that I found recently was keep the accessory belts clean and tight.