ladeit

wow I only get 260 at the most out of a full tank

thomas1

I have consistently got over 340 miles, up to over 400 miles per tank, even with crappy California gas. And that is with a lead foot.

WolfyLS460

Now that the temps are lower I'm getting around 25mpg instead of 27-29.
Still beats the regular RX's 22mpg!

dspeecejr

I currently have two RX450h, a 2016 with 12k miles and a 2011 with 94K miles. Obviously I like this model. I get about 29mpg on the 2016. On the 2011, I got similar mpg for the first 80K and then I started to see a big drop...down to 20mpg. I went to several dealers with the problem and was told everything was fine but the poorer gas mileage may be related to my fuel filter. I ignored this suggestion at first but finally contacted Lexus and got them to agree to replace my fuel pump and filter at no cost. That was extremely nice of Lexus but after the replacement I was still getting 20mpg. After reading a lot of posts, I decided to replace the battery since it was original...even thought two different dealers said the battery was ok. After replacing the battery myself, my gas mileage instantly went back to 29mpg! Not sure why this was not recommended by any of the service departments that I visited!

WolfyLS460

Which battery did you replace? Hybrid? Maybe the 'poor mpg' was electronic not the actual mpg.
How is the ride quality of '16 vs. '11?

ukrkoz

I replaced 12V on my TCH and mpg dropped down instantly. I removed trip odo fuse and that reset ECM that governs mpg. Then it went back to normal. I reset ECM's after any component replacement to erase "old habits" from them. Buddy had same issue with his Prius - 12V replacement, drop down in mpg. He pulled fuse, like I did - all good.
Replaced tires on my HiHy - mpg dropped down. Pulled #35 fuse, which is gauges and trip ECM - same result, went back to normal.

thomas1

That is really interesting....So fuse #35? I am going to try that. and see what happens.

TommyTT

Do you have key on or off when pulling and replacing #35 fuse to reset my RX400h ECM?

Lyqki

Damn im getting around 21-22 mpg average. Mixed highway and city some in between averaging 40-80 mph on most roads. The highway speed limit is 86 mph so that pretty much kills my mileage but still i think its worse than it should be. My fuel is 95 octane since thats the lowest you can get in my country. I know the engine had to be replaced a few years ago. This was caused by missing a few oil changes :0 Basically the dash turned into a club and everything started shutting down to a stop. So im guessing since the replacement something has to be off. I dont have a comparison of the before replacment mileage. Ive tried most of the tips posted here to no avail! I just thought that my foot is too heavy and the car has aged a bit. But reading about 400+ miles on a tank, even on older cars, has given me new hope. Im averaging below 300. Never mind getting close to 600. It seems my engine turns on often. Battery levels are ok. But even when roads are empty and the battery is showing almost full charge the engine kicks in. When stationary it kicks in often as well. I will not accept this 22 mpg the quest continues!!!!

borscht

- if any of your driving is done at 80 mph on any roads, you are not going to get the best fuel economy
- air drag starts out as a linear function of velocity but at high speeds it becomes a multiple of square of velocity. The sweet spot is around 50-60 mph, anything above that and you are just fighting against air
- you removed the luggage rack and/or rails didn't you?
- on the low end of speed range, conventional cars are not very efficient but people take advantage of the momentum, roll through stop signs, slow down half a mile before the stop light so it turns green at the right time
- in a hybrid, same as the previous bullet point ^^ but also at low speeds you can prevent the gas engine from engaging but if there are people behind you they will get annoyed

What I am trying to say is the 400 mile on a 12 gallon tank people are those who drive 55 on a 70 mph highway, coast from light to light on battery with a line of people behind them, yet they roll through stop signs as if they are merely 'guidelines' because coming to a complete stop and then starting from 0 mph ruins their fuel economy... Some of their driving habits are NOT safe.

If that is not how you drive, you will not get 400 miles on a tank. Yes you could drive like this for a day. But you would have to drive like this for **several tanks** (to get good average AND to let the computer adapt).... its all about the driving style trust me... I average about 25. My wife drives my car for a day and its down to 21... She is just all about getting her stuff done.

We have a guy here at work who is a big MPG junkie. He has a small two door hatchback (civic or something). Not a hybrid. He's removed everything that's belt driven, no alternator either. electric fans only. Because of no alternator, he has to charge the battery during the day, so in the morning I see him put up the solar panel in his back window. He claims crazy fuel economy like in the 60 mpg range, but that's more of a lifestyle at this point...

MACRX400h

I changed my dying 12v battery and changed my air filter. I also started using B mode which appears to get more help from the battery. In D, it appears to do much less. Can’t cruise control in B, but my mpg has jumped from 22 hyper mpg vigilant driving to 25-26mpg mild go with the flow driving.

The battery is far more engaged in B mode and makes me wonder whether the infamous “update” I read about lowering mpg for the RX-400h only affected the D mode.

If D mode engaged the battery in the same way B mode did, My RX-400h would be budget luxury hybrid heaven.

TommyTT

My wife recently did a 818 mile round trip from SE AZ to the Hopi Res and got 29.9 mpg. And trip was in mountains 40%. 2008 RX400h. With 134,250 miles on clock.

TommyTT

Just got home from 'birding'. 68 miles and 33mpg. No faster than 50mph.

professorm

Mine averages 24 mpg both city and highway, with my wife driving. I like in 100% flat area, close to sea level.

mnewxcv

might want to check tire pressure, 24 mixed is a tad low. I get about 24 in the winter with mostly highway driving, but closer to 27 in the summer with more city mixed in.