'99 just doesn't roll very "efficiently". Is this normal?

[sps513]

Hi gang, good day.

I've been driving my dad's '99 RX300 for a little while and I have been amazed at how poorly it rolls.   He's the second owner, having purchased it in '02, and has really taken very excellent care of the car.  It has 140K miles and is in superb condition.  He's always mentioned this and has noted that it doesn't get the best gas mileage certainly due to this.

It's not a worn or failing part...it just doesn't roll well.   When I shift into neutral on a downhill, it hardly picks up speed at all.   This is so odd for me comparing it other cars I've owned including my '98 Acura RL, '06 Honda Odyssey, and 2010 528i xDrive.   On each of those cars when I shift into neutral to roll, it feels like I "break free" and the car takes off.   My dad and I believe it is probably just that this was an early AWD car and there have been improvements since then??     Just wondering if anyone else could confirm or deny this similar condition on your own car.

 

Thanks,

Steve

Cincinnati. 

[RX400h]

Our RX400h rolls just fine. Has anyone looked at the brakes? After a drive, carefully touch each wheel to see if any is hot. That would indicate pad-to-rotor friction when no braking is being applied, often.

[sps513]

No, it's in fine mechanical condition, including the brakes.... which were obviously a good first place to consider, I agree. 

It has been like this since the day he purchased it from the dealer, and coincidentally I can push the vehicle in neutral on level ground without issue.   (My young daughter and I had to push it out of his garage recently to jump it since it had been sitting for many months.)  I also tested in on minor inclines by shifting into neutral and it rolls both forward or backward immediately.  But if you're driving, it just is not a free rolling vehicle like all the others I've ever driven.    It's very curious.

[RX400h]

That's perplexing. Our all-wheel drive system is certainly newer and configured differently, since it is a hybrid. What fuel mileage was he getting on average? Did he ever check by looking at the odometer and gallons to fillup?

[sps513]

Funny you should ask that.  🙂   My dad was meticulous in keeping records of every time he bought gas and what his mpg was.   I remember as a kid he would have one of us do the math each time, without fail, because "I need to have the information for my records....and it's good for you guys to keep your long division skills sharp".

I'll have to get out the book and review it, but as he just told me the other day it would only get around 20mpg.   Rarely, if ever, any higher.

 

 

[RX400h]

That's good that he encouraged using math for real-life use.

I recall in the early 2000s, speaking with RX330 owners who told me they were averaging 18-20 MPG, depending upon the ratio of highway to city driving. I think even Consumer Reports listed that vehicle as having an average fuel mileage of 19. Ours has always been about 25-27 with a mixture of highway and city driving, but then again, it's a hybrid. The new Toyota Sienna hybrid vans are averaging about 30 MPG - fantastic for such a large vehicle that is not the best, aerodynamically-speaking.

[sps513]

Interesting update on this subject....

I had the transmission fluid flushed, with the understanding from the tech that this always goes 1 of 3 ways--either nothing changes, the trans does "better", or the trans has new problems.

Well, I am pretty certain that this had a positive influence on the car's "rolling ability".   I have re-visited some hills where previously the car would actually lose speed while rolling down the hill, and now I am actually at least maintaining speed if not slightly increasing.   I really do believe the difference is noticeable.   

Sadly, it did NOT correct the problem with the car not upshifting from 2nd into 3rd gear for the first 1.5 to 2 miles when starting cold.  It seems the trans has to warm up before it will finally shift into the higher gears.   But, I can live with that inconvenience since that's almost the distance to get out of my neighborhood anyway, and 25MPH is a good speed in the neighborhood.

[fernandolpa]

Hi, I drive a 2001 AWD, with 220's miles. I live in Spain, our orography is full of hills, not the best for MPG. Although I have an average after 22 years of 18,80 MPG, including city highway off road...and my highway driving is close to 90 MPH cruise. Driving on highway at 70 MPH average is 23,45 MPG.

Aerodynamics is the clue for the problem you mention. My BMW F11 can get 85 MPH in the same hill that the RX makes hardly 70 MPH in neutral.

Check tires pressure, my experience is that Lexus recommendation is quite low for the weight of the car. I have 2.9 bar instead of 2.2 recommended and the car goes much better and improves mileage.