lawjaii

14 rx350 here with only 25k miles, owned since new

Recently i've moved to downtown area of my city, been doing 95% city stop go traffic driving. Hence, fuel economy went up greatly to around 12 MPG overall.

I have some concerns. First of all, the transmission seems to be holding gears way longer than before. I feel this is the main reason why the crappy MPG.

Even when im driving at midnight with no traffic and mostly green lights, im still getting only 15 MPG. which is horrible

I read from forum about resetting adaptive transmission.. is this a myth or actually exist? Some say its bad to reset it..

I am hesitant to pull the battery at this point to test it

Any advice?

iolmaster

iTrader: (1)

Here is the way we do it in an SC430 I am not sure this will work for the RX. The most common way to do it is pull the negative battery terminal for about 2 minutes.

1. Get in your car and insert key. (It doesn't matter if you close the door or not.)

2. Turn the key to the on (not start) position.

3. Press the gas pedal to the floor.

4. Hold the pedal to the floor for five seconds, then turn the key back to the "off" position (don't remove the key), then release the gas pedal.

5. Wait 2 minutes.

6. Remove key.

7. Done

ThumperPup

i don't know how this would work in the 2014 RX the OP has because their is no key to insert it is all pushbutton and if your foot is on the break when your pushing the button the car is going to start so step 4 is not going to be possible for the vehicle with Push to Start button
i know over in the 5th gen ES part of the forums their are 3 ways to fix a transmission flare which this sounds like and that is to replace the transmission or replace the valve body
or go to a dealer and have the transmission reprogrammed at the dealer via computer i think the last verison is the cheapest and what most people would choose to do i hope

Clutchless

The vehicle is still under warranty. Let the dealer inspect it. Also check your tire pressure and air filters as the simple things like low tires or a dirty air filter can have a big effect on mileage.

vlad_a

And I bet your gas stations also switched to winter mix, which hurts MPG along with low temps.
Try putting premium gas in and see if you regain a couple MPGs.

iolmaster

iTrader: (1)

OK I'll bite. Why would you gain a couple miles per gallon putting premium in? That makes no sense.

vlad_a

Regular runs on retarded timing to mitigate knocking. Premium can advance timing, which may improve efficiency. YMMV.

iolmaster

iTrader: (1)

Only if you have the compression ratio to take advantage of it. The RX does not.

raylor4

We have an '11 RX350. It runs on regular but runs better on premium. On regular, we get about 300 miles to empty at fill up. On premium, we get about 335 miles to empty. Both of these dashboard read outs are after using either gas for about a month. So, with premium, we get about 2 mpg more than regular, and the shift points are lower. Go figure. I hate paying the extra for premium, but the engine and trans run noticeably smoother. So be it.
I agree with Clutchless who said a dirty air filter will change shift points. Makes sense since one of the parameters for the shift point is the mass air flow sensor, downstream from the air filter. My 2 cents. Thanks for listening.
Ray A.

parolla

I followed this procedure on my 2011 is250 to remedy the slow upshifting,and it worked. Much easier than pulling the battery cable and having to reset everything else too.

rababich

The 2011 RX350 was programmed to run on premium, but I've read it will run on regular, maybe after the computer sees the difference in engine performance.
The 2012+ RX350 was programmed to run on regular, so it might not run much better on premium.
We bought our 2012 because it was the first year the RX350 was advertised to run on regular.
Edmunds specifications pages show the same EPA Estimated Mileage for both.

User 122922

I had my 08 Gs 350 for about 2 month now, and I noticed at the beginning the transmission shifts pattern weird and takes longer time between shifts, what I did is I took off the negative terminal on the battery for like 15min then I put it back, and I didn’t actually have to reprogram seats or radio channels or anything don’t ask me how ,, man let me tell you this the transmission shifts now like dream I was really impressed, shifts very fast smooth I don’t hear anymore the whining sound from gear 1-2 and it feels more quitter and picking up much faster than before I also got more mpg as well from 22mpg to 27mpg on highway, so basically It did work out for me on my Gs 350 , good luck 👍🏼

rababich

I don't know if this procedure works on a 2012 RX350 with Push To Start, but you can push the START button and get the system into the RUN mode with the radio ON for example.
Steps 3 & 4 of the procedure uses the gas pedal, not the brake pedal.
The procedure might use insertion/ removal of the key for some purpose so it may not work with a Push To Start system.