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Hesitation On Acceleration--2012 RX 350

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Old Aug 5, 2014 | 09:00 AM
  #121  
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You don't want the lag, don't drive a vehicle with 270 hp and a drive by wire system. It's that simple. it's working the way it's supposed to and is not specific to Lexus. You go to any brand and every driver who didn't realize what they were getting will have the same complaint. Gas pedal is not directly connected to throttle.

If you want to test whether your lag is abnormal. Find an empty road, stomp on the pedal, count 7.7 seconds and look down. (yes F-Sport too). You see 60mph or something close to it, sorry to tell you but you're driving an Rx 350.
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Old Aug 5, 2014 | 10:33 AM
  #122  
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and it`s a 4300lb vehicle! lets not forget about that.
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Old Aug 6, 2014 | 11:30 AM
  #123  
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I wholeheartedly (and respectfully) disagree. My honda odyssey was drive by wire and didn't have this lag. A drive by wire system shouldn't make any difference. It's the way it's set up, not an inherent, secondary effect of the system. In fact, the drive by wire system is supposed to make the throttle MORE sensitive....which is why many VERY expensive sports cars have them (e.g., the Ferrari Enzo!). This issue is a design flaw by lexus, plain and simple. The question is whether this issue in the RX extends to actual Lexus sports cars. From what I can see online, the LFA has a drive by wire system too, but I haven't heard of anyone complaining of a similar lag (though I don't know anyone with an LFA) . Also for the record, our new Acura MDX doesn't have this problem either. It's 300lbs heavier than my F sport, and is drive by wire as well.
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Old Aug 6, 2014 | 12:12 PM
  #124  
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Originally Posted by viperdoc
I wholeheartedly (and respectfully) disagree. My honda odyssey was drive by wire and didn't have this lag. A drive by wire system shouldn't make any difference. It's the way it's set up, not an inherent, secondary effect of the system. In fact, the drive by wire system is supposed to make the throttle MORE sensitive....which is why many VERY expensive sports cars have them (e.g., the Ferrari Enzo!). This issue is a design flaw by lexus, plain and simple. The question is whether this issue in the RX extends to actual Lexus sports cars. From what I can see online, the LFA has a drive by wire system too, but I haven't heard of anyone complaining of a similar lag (though I don't know anyone with an LFA) . Also for the record, our new Acura MDX doesn't have this problem either. It's 300lbs heavier than my F sport, and is drive by wire as well.
My GS before it was modified, had the same lag.

Google: https://www.google.com/search?q=driv...hrome&ie=UTF-8

Ford, BMW, Honda, VW, Toyota, Lexus (you guys, lol) are on page 1. Page 2 = Pontiac, Mazda, Subaru, Dodge, etc.

It's still a simple equation. Do a 0-60 test and see what your numbers are. If it's in range, then the RX is acting like an RX.

Way more productive. And much easier to go to the dealer and say. "My RX is getting 9 second 0-60 times, fix it"

The thing tops out at 112mph. Getting somewhere quickly was never it's intent.
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Old Aug 7, 2014 | 09:16 AM
  #125  
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Originally Posted by oohpapi44
My GS before it was modified, had the same lag.

Google: https://www.google.com/search?q=driv...hrome&ie=UTF-8

Ford, BMW, Honda, VW, Toyota, Lexus (you guys, lol) are on page 1. Page 2 = Pontiac, Mazda, Subaru, Dodge, etc.

It's still a simple equation. Do a 0-60 test and see what your numbers are. If it's in range, then the RX is acting like an RX.

Way more productive. And much easier to go to the dealer and say. "My RX is getting 9 second 0-60 times, fix it"

The thing tops out at 112mph. Getting somewhere quickly was never it's intent.
I do agree with you, the RX is performing as it should. And I am not arguing that a better throttle response would make the car faster. I didn't get the RX to go from 0-60 in 5 seconds. But the throttle lag is a daily nuisance. My point was that this is how lexus designed the throttle, pedal, transmission and engine to respond in an effort to enhance fuel economy. While I understand the rationale, it is really obnoxious. I paid closer attention today. From a stop, I can push the pedal down at least 1-1.5 inches and the engine doesn't even twitch. With that much laxity, no wonder it seems to take forever for the transmission to get the signal to downshift. As as I said before, having the paddle shifters fixes this for the most part while driving, but from a standstill, it is still really annoying. My other point was that this lag isn't the result of the drive by wire system....more the result of how lexus designed it to work.
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Old Aug 7, 2014 | 09:37 AM
  #126  
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Originally Posted by viperdoc
I do agree with you, the RX is performing as it should. And I am not arguing that a better throttle response would make the car faster. I didn't get the RX to go from 0-60 in 5 seconds. But the throttle lag is a daily nuisance. My point was that this is how lexus designed the throttle, pedal, transmission and engine to respond in an effort to enhance fuel economy. While I understand the rationale, it is really obnoxious. I paid closer attention today. From a stop, I can push the pedal down at least 1-1.5 inches and the engine doesn't even twitch. With that much laxity, no wonder it seems to take forever for the transmission to get the signal to downshift. As as I said before, having the paddle shifters fixes this for the most part while driving, but from a standstill, it is still really annoying. My other point was that this lag isn't the result of the drive by wire system....more the result of how lexus designed it to work.

Understood. My post was more to those who think something is not working properly.

This would have been the remedy but just checked their site and they don't list the 3rd Gen.

Sprint Booster, a Plug-n-Play Performance Upgrade for your Model Year 2000 or later vehicle. This is an upgrade that you can feel with normal everyday driving, not just on the track at redline like most other performance upgrades!

30-DAY MONEY BACK GUARANTEE* This is a product that you need to 'feel' to believe - we are so confident that you will LOVE this product, we are offering a 30-day money back guarantee - no questions asked. What is SprintBooster?


Most cars in the 21st century have replaced the more conventional throttle cable for an ECM (Electronic Control Module) that translates how hard the pedal is pushed into electronic signals in order to provide power to the wheels.

The ETC (Electronic Throttle Control), which is also known as Drive-By-Wire, has the unfortunate downside of delayed response and subdued acceleration, which can create problems in certain situations such as up-hill starts, quick gearchanges and overtaking.

Sprint Booster overcomes this throttle response delay for your vehicle by providing crisp, on-tap acceleration for whenever the driver demands it.
http://www.sprintboosterusa.com/c-197-at.aspx
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Old Aug 7, 2014 | 10:04 AM
  #127  
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Originally Posted by viperdoc
From a stop, I can push the pedal down at least 1-1.5 inches and the engine doesn't even twitch.
I don't have anywhere near 1-1.5" of dead travel in my pedal. Yikes!

Last edited by JDR76; Aug 7, 2014 at 11:30 AM.
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Old Aug 7, 2014 | 02:03 PM
  #128  
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Originally Posted by oohpapi44
Understood. My post was more to those who think something is not working properly.

This would have been the remedy but just checked their site and they don't list the 3rd Gen.



http://www.sprintboosterusa.com/c-197-at.aspx
By the way I looked at this web site, the module lists RX model 04-09 so am not sure if it will apply to our later models.
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Old Aug 11, 2014 | 04:58 AM
  #129  
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I can't agree with you because my hesitation problem is not repeatable. If it was I would have something to demonstrate to the dealer. Going back on this thread I find several owners had similar results with the problem and when getting the dealer to test drive they heard, "Did not find a problem."

Google "Toyota acceleration by wire system" Look at the diagrams, which show components of system inputs. If a less than perfect design or a faulty component then a less than perfect acceleration response can indeed happen. The link http://www.forbes.com/2010/02/23/fli...ss-recall.html does not specifically discuss the "hesitation" problem, but Toyota's frightful unintended acceleration issue I feel it is related to the "hesitation" issue as well.
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Old Aug 11, 2014 | 08:22 AM
  #130  
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"


Originally Posted by viperdoc View Post
"I do agree with you, the RX is performing as it should. And I am not arguing that a better throttle response would make the car faster. I didn't get the RX to go from 0-60 in 5 seconds. But the throttle lag is a daily nuisance. My point was that this is how lexus designed the throttle, pedal, transmission and engine to respond in an effort to enhance fuel economy. While I understand the rationale, it is really obnoxious. I paid closer attention today. From a stop, I can push the pedal down at least 1-1.5 inches and the engine doesn't even twitch. With that much laxity, no wonder it seems to take forever for the transmission to get the signal to downshift. As as I said before, having the paddle shifters fixes this for the most part while driving, but from a standstill, it is still really annoying. My other point was that this lag isn't the result of the drive by wire system....more the result of how lexus designed it to work."

Somehow I feel my problem has become lost in the shuffle . The Lag or Hesitation I'm getting
is not between the throttle and the engine but rather between the engine and the transmission.
I beleive the Trottle/Wire issue being tossed around isn't part of my problem.
My Engine responds immediately ( as witnessed by the jump in the Tachometer ) and then the Tranny engages, sometimes with a jerk--sometimes Normally.

I'm really not trying to peel rubber, just exit an intersection, and would like it to happen like
driving a Luxury Vehicle.

Last edited by chazman6; Aug 11, 2014 at 01:27 PM. Reason: Reference earlier post.
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Old Aug 11, 2014 | 09:57 AM
  #131  
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Originally Posted by mcdgary
I can't agree with you because my hesitation problem is not repeatable. If it was I would have something to demonstrate to the dealer. Going back on this thread I find several owners had similar results with the problem and when getting the dealer to test drive they heard, "Did not find a problem."

Google "Toyota acceleration by wire system" Look at the diagrams, which show components of system inputs. If a less than perfect design or a faulty component then a less than perfect acceleration response can indeed happen. The link http://www.forbes.com/2010/02/23/fli...ss-recall.html does not specifically discuss the "hesitation" problem, but Toyota's frightful unintended acceleration issue I feel it is related to the "hesitation" issue as well.
It is very scary. Mainly because you would think that by now, they would have the technology/engineering for the "go pedal" down. I wonder if nuclear subs have "hesitation" issues )))))))
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Old Aug 14, 2014 | 07:21 AM
  #132  
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Originally Posted by CapeDave
It is very scary. Mainly because you would think that by now, they would have the technology/engineering for the "go pedal" down. I wonder if nuclear subs have "hesitation" issues )))))))
These would be electric - immediate torque!
Like a Tesla.
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Old Aug 14, 2014 | 08:16 AM
  #133  
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Originally Posted by vlad_a
These would be electric - immediate torque!
Like a Tesla.
Dream car! So true. I would like to experience that car as soon as possible. I know I cannot afford the car. But I wonder if they charge for a test drive ?
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Old Aug 14, 2014 | 08:24 AM
  #134  
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Originally Posted by CapeDave
Dream car! So true. I would like to experience that car as soon as possible. I know I cannot afford the car. But I wonder if they charge for a test drive ?
The test drives are free. I have been recommended to absolutely take one.
Now, the next best alternative is the RX450h.
It has no hesitation or lag and about as electric as it gets.
A bit of torque-steer, though.
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Old Aug 14, 2014 | 07:24 PM
  #135  
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Originally Posted by vlad_a
The test drives are free. I have been recommended to absolutely take one.
Now, the next best alternative is the RX450h.
It has no hesitation or lag and about as electric as it gets.
A bit of torque-steer, though.
From what I have heard, I agree about the 450h. It is a very well done hybrid. The Tesla is truly the car of the future. I would love one. Maybe their $35K one they are supposedly coming out with in 2015-16?
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