BearsLexus

Thanks for all the GREAT info and instruction LexMex!! I am going to undertake quite a bit of this myself this coming weekend when I change my oil!
Anthony

CharBaby

Hello. New member here! '01 RX w/AWD, owned since new! ~ mileage is <80K

I have also done many thing that other members have tried with little change in MPG.
I have changed out both A/F sinsors and the downstream O2 (all due to CEL Codes)
Cleaned the MAF, IAC and changed the PCV.
Maybe a new set of plugs are in order but, I'd never really know if the plugs would change things til I try.(engine start & runs fine)

What I really find that gives the best MPG is easy driving w/ CC. If the vehicle is drive reasonably, the City MPG can reach 18-19 MPG and over 22 Hiwy. And this was with the smooth/quiet G/Y Integritys(which I disliked). I now have the G/Y ACT's(3 years now) and there really is little difference.

OTOH, when driven with even the slighest verve, the MPG will drop to what other member have been complaining about(which will vary).

Now, I don 't think that this is great MPG by any means but, it is what it is! Other SUV's/CUV's may get better MPG but, many are even worst.

Thanks for listening!
CB

imherenow

i get 20.5mpg in mixed city and hwy.(mostly hwy). but now i have having issue with rough start. So time for a IACV clean up.

lexa004

i get about 18mpg strictly city.
when i first got my car (got it used) the mileage was horrible i was only getting 14mpg if i was lucky. but my poor car came with a load of problems within the first month of driving. it was clear the pervious owner didn't take wonderful care of the poor car. once we fixed them the milage started to shoot back up.

Brcobrem

Since I serviced the MAF sensor (Mass Air Flow sensor), I now get 24mpg at 70 mph, 25mpg at 60 and 65pmh, and 26mpg @ 55mph. According to the directions on the CRC MAF Cleaner can, that valve is supposed to be cleaned every time the air filter is changed. Two screws and it’s on top of the air cleaner housing. Solvent is $9. Takes 5 minutes to remove the sensor, clean it, and put it back.

Here's a "before" pic of the diode:
https://skydrive.live.com/redir?resi...0CBD3BA347!311

Here's an "after" pic of the diode:
https://skydrive.live.com/redir?resi...0CBD3BA347!311

My experience was that the MAF cleaner caused the O-ring on the sensor to swell a little. I dried it (and the diode and platinum wires) with PC air cleaner can, then let it dry about 1/2 hour, and it shrank back to size. I noticed that the o-ring was pinched at one place when the factory installed the sensor. It's a tight fit back into the air cleaner housing. I used a hint of silicone grease on the o-ring outer surface and the sensor went back into the hole without binding this time.

Quite a jump from the 14.5mpg it was getting wouldn’t you say?
Now I am very happy with fuel mileage. Think I’ll keep it :->

Here's a pic of the debris that flushed out of the IACV valve. I pulled off the hose on the bottom of the valve (yes, pulled it off because you can't get to the factory clamp clip), then used carb cleaner for about 5 seconds and flushed it through into a paper cup :
https://skydrive.live.com/redir?resi...0CBD3BA347!313

Here are a couple "Funstuff" pics:
https://skydrive.live.com/redir?resi...0CBD3BA347!315
and
https://skydrive.live.com/redir?resi...0CBD3BA347!315

Thanks to all for the heads-up on the mileage fix.

Regards,
Brcobrem

P.S. Skydrive is a PITA to use. Wish I never got sucked into using that.

carguy07

Thanks for the pics. Looks like you are pretty low on coolant. might want to top that off with some Toyota red.

Brcobrem

Carguy07, I started new post at:
https://www.clublexus.com/forums/rx-...ml#post7332557

Thanks!

hypervish

That's great mpg. I just returned from a road trip to MI/IL today, and on one tank I averaged 24.8 mpg going 80-85mph, the entire time. I consider that amazing mpg, especially considering I had the A/C on. There was a tail wind, which I'm sure helped a lot.

Brcobrem

Hi hypervish,

Just for the record, my mpg tests where done on completely flat Florida turnpike with little to no wind that day.
I did the tests on long stretches between overpasses so there's no hill climbing or descents whatsoever.

I also confirmed that that mpg computer on the RX300 is as accurate as the manual method where you fill up the tank noting the current mileage, run the tank down to 1/4 or 1/8 tank, fill it up again noting the gallons to fill it up and noting the ending mileage. Divide elapsed miles by gallons to refill the tank (ie. miles per gallon(s)).

Nothing new here, but just a couple facts for the record.

Regards,
Brcobrem

BearsLexus

Good stuff Guys... I just cleaned my MAF Sensor, too... it was BLACK!! I don't think it had ever been cleaned since new... It appears I gained a smidgen of MPG... not extremely noticeable, but then I was already getting the low-mid-20s per gallon on the Flats... I may be up to 24-25 mpg on the flats now... @ 70 mph.
I've been following along with all the discussions here and performing all the same work as you have and have gotten nice results...
The one set of maintenance that I have yet to do, but really want to get to is the Rear Diff, and Transfer Case Fluid changes... I have my Mobil 1 full Synth, Gear oil just waiting and the screw on pump ready to go; I just need to get it up on a lift and do it... Then I'll have Mobil 1 Full Synth for ALL my Lubricants.

Love My Sexy Lexy!

Bears'Lexus

utahrx300

99' rx300 awd w/170k. 91 octane fuel always. Brand new transmission, timing belt, water pump, front exhaust manifold, NGk plugs. Mileage was still around 13.5mpg very bad, considering its driven really well by my wife and myself.

I replaced the exhaust manifold because it had a four inch crack right above the o2 sensor. Hoping the mpg would go back up to 20+, but no. So I Cleaned the PCV hose that was clogged and new PCV UNIT, cleaned the iacv and hose, cleaned maf sensor, changed oil and air filter, Mobile1 5000 oil.

Now mileage is finally back around 19 mpg, just back on road so it should get better and I will report back soon with better data.

utahrx300

Well mpg is up better than ever. But now there is smoke on startup for about 15-30 seconds. It's grey smoke and I think with higher mileage it could be the valve seals. First I will try a thicker oil and some cleaner.

Baetke

I get 20.5 combined city/hwy and 26-27 on the freeway if I keep my speed below 65.

The best tip I got for fuel economy was from my gas station attendant. I live in Oregon and we used to switch to "oxygenated" fuel in the winter (thats the crap gas with ethanol in it). I could always tell when they switched that blend because my mileage would immediately drop by 10%. I suppose the tree huggers think burning 10% more gas to go the same distance is somehow going to stop global warming... but I digress. My gas station attendant recommended upgrading from regular gas to "plus" grade. I tried it and noticed an immediate improvement in power and fuel economy. The gas costs 10 cents more per gallon, or about 5% more than regular, but my mileage went up by 10%, so I'm actually paying less per mile driven, and the car runs better. Had exactly the same result with my wifes 2004 ES330. I figured if a little was good, a lot must be better, so I then tried premium grade fuel. Alas, no further improvement so I just burn plus grade now.

Baetke

Hypervish,
Just to be clear, the red bulb in your picture is not a diode, it is a thermistor. A thermistor is a resistor that changes value with temperature. Also, the red bulb is the intake air temperature IAT sensor, not the MAF sensor. If you measure between pins 4-5 on the connector you should get between 2.21k and 2.69k ohms at 68 deg F for the IAT sensor.
The MAF consists of the two things that look like resistors that are buried down inside the plastic housing next to the IAT sensor along with some electronics to generate a voltage proportional to the amount of air flowing through the intake. They also need to be cleaned.

hypervish

Those are not my pictures, they belong to Brcobrem.

We (CL) commonly refer to that thermistor as a diode, or the red thing. LOL

Thank you for clearing that up.