Sobus666

Hey

I recently bough a 2016 Lexus RX350 AWD
It was a certified pre-own lease car.
I bough it with 22k miles on it.
Right now I have a little over 25k miles
Issue I'm expirencing with this car is pretty hard to demonstrate and explin but it is there.
When I'm driving the car 55 m/h or over that on flat surface or downhill I hear a knocking sound when depressing and pressing the accelerator pedal.
I isulated that issue pretty well and it sound like it is coming from the front end diffrential or
front drive shaft.
I visit the dealr last week , test drove the car with a lexus master tech and was told to drive the car in sports mode and use premum gas.
They did update my ecu sofware to change shift pattern.
But problem still exist.
I dont think it is a transmission issue.
Did any of You guys had an issue like this ?
Any sugesstions ?

ravenuer

If Lexus wanted you to use premium gas and drive in Sports mode, they would have designed it that way. They didn't, so therefore your dealer is wrong. If I were you, I'd bring it back and say it's a CPO, either fix it or give me my money back.

Cocal

In case you missed the thread where it was stated that all the tests by Lexus were conducted using 91 octane (premium) that was the standard. In the manual it tells you not to go below 87 that's a warning not a recommendation!

Also what makes you say that it wasn't designed for sport mode, I'm saying this because I don't have any of these problems, when in sports mode it's more responsive and more enjoyable to drive in eco it's a pig like most other vehicles

ravenuer

I disagree. First he has to make sure he's using at least 87 gas. If his car knocks on 87 and there's nothing wrong with it, then the manufacturer would have to specify something higher. Can't have it both ways.
Secondly, when he starts his car, I believe it defaults to Normal mode. If he's required to change it in order for it to run properly, then it should default to Sport mode.
Sorry but the dealer wants to weasel out on this one.

Cocal

That's right, the manual warns not to go below 87, but all the tests were made using 91, the computer will compensate if using 87 but will not if using anything below that level.
Also the driving mode will default to the last setting, so if you were in sports mode when you shut it off that will be the mode that will exist when you start it again.

Sobus666

Thank You for respond.
I am planning to visit dealership this week.
Will bring the subject up again.
If I will get negative respond this time I will try to get Lexus cooperate or regional manager involve into this issue.

Nail34

So why is the master tech disagreeing with the Lexus engineers and requiring 91??
If the car is shut off in eco or drive it will stay in eco or drive when started. If the car is shut off in sport or sport+ it will default to drive when started.

mikemu30

Incorrect - mine ALWAYS defaults to NORMAL regardless of the last setting.

JSracer

my 450, sport defaults to normal, eco remains on eco

ravenuer

As does my 2017 RX 350.

mikemu30

Got it - never used ECO and never will.

Cocal

It may be incorrect for YOURS, but not for mine. It always defaults to last setting.

Cocal

I use 91 as this is what the engine was designed and tested for, but one can use lower or higher settings and the computer will compensate, but manufacturers know that there is a great resistance to premium fuel so they don't say it in the manual, however they warn not to go below 87. Yet even this is seen by some as a recommendation.

My car defaults to whatever setting was last selected, I don't have sport + only sport norm & eco

Sobus666

That's correct.
Mine does go back to normal setting after car restart as well.

SoCalRX

Sounds like there's a software settings difference between Canada and US. The US might reset to a determined setting to attain EPA numbers.