Hesitation problem at various speeds (TSB info post #159)
08-18-17, 12:26 PM
#511
Richstang, Thanks for the info. That is the same TSB that was installed on mine. It worked very good for a couple of months but then begin to hesitate again. Dealer stated there wasn't anything else they could do at this time. However, they were exspecting Lexus to come up with something new. Ha what a joke. My next comment is ridiculous but here goes so don't everyone jump on me. I filled my vehicle up with shell premium gas and the hesitation disappeared. I could not believe it and still am confused but it happened. Don't understand why but it worked. May start again but this tank is wonderful. Will try one more with premium and check it out. Now, folks don't light up my computer. I may be old but sane. There is no reason for this to happen in my opinion but it has in reality.. I have no further explanation.
08-18-17, 07:12 PM
#512
I also notice that the first mile or so after a new tank of gas (regardless of octane) the car drives real predictably and smooth. Soon after the crappy hunting and hesitation return. We also talked in this thread that the first min after the morning start up can be smooth shifting. Perhaps the car is trying to be too smart with the shifting that it actually leads to this crappy experience. It's really about how much the car will hold gears 1-3 vs jumping so fast to 4 which is when you get all the ridiculous upshifts and downshifts.
08-18-17, 07:55 PM
#513
Intermediate
As everyone knows, the tranny upshifts very quickly I assume in an attempt to increase mpg. I drive up a fairly steep hill to my home and in D mode as I start the climb the car searches for the appropriate lower gear and I have to push down on the accelerator for the car to down shift into that lower gear, quite herky jerky . Therefore I always use M mode, start in 1st and upshift into 2nd at 8 mph and leave it there till I turn into my driveway and then as I slow down it will automatically downshift back into 1st. I use M mode a lot, makes me feel like I'm driving a stick shift, I miss my stick shift. LOL
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FastFord (08-19-17)
08-18-17, 08:32 PM
#514
At the end of the day, what it amounts to is the RX transmission is a POS. It's clunky, it hesitates, it makes irrational shifts and Lexus states it's normal. Unfortunately, in the name of MPG, I believe this is the new reality for the next few years until the engineers figure things out. Acura had the same issue with an 8 speed. Unfortunate our current options are ****ty transmission on a Japanese car with excellent longevity or decent transmission on a European car that will crap out with insane repair bills at 90k miles..... Choose the lesser evil.
08-19-17, 04:49 AM
#515
I think the reason why some of us, including myself feel the car runs better from a cold start could be the open loop, closed loop senario. The computer will switch from open loop to closed loop when the 02 sensors get up to temperature and computer can operate off the learned parameters. Mine shifts perfectly unitil it gets up to full operating temp.
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JCanada (08-20-17)
08-19-17, 04:59 AM
#516
At the end of the day, what it amounts to is the RX transmission is a POS. It's clunky, it hesitates, it makes irrational shifts and Lexus states it's normal. Unfortunately, in the name of MPG, I believe this is the new reality for the next few years until the engineers figure things out. Acura had the same issue with an 8 speed. Unfortunate our current options are ****ty transmission on a Japanese car with excellent longevity or decent transmission on a European car that will crap out with insane repair bills at 90k miles..... Choose the lesser evil.
08-19-17, 05:01 AM
#517
I think the reason why some of us, including myself feel the car runs better from a cold start could be the open loop, closed loop senario. The computer will switch from open loop to closed loop when the 02 sensors get up to temperature and computer can operate off the learned parameters. Mine shifts perfectly unitil it gets up to full operating temp.
As stated in an earlier post, I to go up a hill in the morning and I might as well floor it to avoid the gear jumping.
08-19-17, 06:11 AM
#518
That is really strange, seems like there is no consistency with this car. On a more positive note, overall I feel like the drone has gotten better Have 6k miles now, maybe the exhaust note changed slightly. At least its getting better not worse, I can live with it the way it is but still wish they would come up with some sort of fix. I drove the wifes Tahoe last night and couldn't believe how much smoother the engine is. I really wish the Lexus was that smooth, I would buy another in a second if it were. Maybe I just got stuck with a bad one, but you would think with all the latest technologies these kind of issues would be a thing of the past.
08-19-17, 07:12 AM
#519
Yup there doesn't seem to be a condition that is consistent. It's all over the map, some weeks perfect, then it goes funny. Glad it's great most of the time and frustrated when I take the car out a second time in a day and all of a sudden it's like driving another car.
08-19-17, 11:22 PM
#520
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I noticed the hesitation on my 2017 RX the day after I took delivery. I drive now in S+ mode and the low rpm hesitation is barely noticeable. But Lexus has to come up with a fix. I have spoken with two former Lexus service managers who say it is computer programming issue.
Hulatee
Hulatee
08-20-17, 12:01 AM
#521
The hesitation doesn't worry me so much if you don't hear the engine/tranny changing revs/gears - just turn the sound system up LOUD!!
09-01-17, 06:45 PM
#522
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Transmission is a pile of garbage
Posting for my 4th Rx model so I'm not a noobie and I know what I'm talking about.
Thought it was just the government mandated eco mode, but after several weeks of trying both normal mode and sport mode, the transmission performance is a complete joke. While traveling at 70 mph on a highway and pulling around to pass a slower car, the RX350 actually paused and lurched for a few seconds, almost like the electronic parking brake kicked in. This was all while I nearly had it floored. This issue happens daily at various speeds, not just highway speeds.
There are many design flaws and software flaws with the Rx350. Not to mention the absolutely insane ergonomics layout of controls.
But a major transmission design flaw is unacceptable and unsafe.
Thought it was just the government mandated eco mode, but after several weeks of trying both normal mode and sport mode, the transmission performance is a complete joke. While traveling at 70 mph on a highway and pulling around to pass a slower car, the RX350 actually paused and lurched for a few seconds, almost like the electronic parking brake kicked in. This was all while I nearly had it floored. This issue happens daily at various speeds, not just highway speeds.
There are many design flaws and software flaws with the Rx350. Not to mention the absolutely insane ergonomics layout of controls.
But a major transmission design flaw is unacceptable and unsafe.
09-01-17, 06:50 PM
#523
Lexus Test Driver
For you.. Sorry to hear it.
But for me? Works fine. On sport+ mode the throttle is quick and responds immediately. I do get a delay on normal mode the few times I floor it.
I think there is a service for a transmission remapping or something.
But for me? Works fine. On sport+ mode the throttle is quick and responds immediately. I do get a delay on normal mode the few times I floor it.
I think there is a service for a transmission remapping or something.
09-04-17, 11:38 AM
#524
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Transmission Change
Here in Australia I've been running premium fuel for a while now and hesitation was much improved but still not perfect so still using Sport mode to smooth things out more. Car now drives well MOST of the time but still on occasions will hesitate randomly. Don't know if it's the fact the tranny learns your driving style and adapts then you change your style coming into a corner (more or less throttle) and the system is now wrong for that corner. I've found that driving the car around the rural town I live in at a slow rate,very relaxed, no traffic the car feels great. Go to a city like Sydney where the going is much faster and the car doesn't like it as much at all, often throwing in a hesitation here and there. Obviously there's a problem with the mapping of the tranny - if I try manual mode the gear changes are a treat; very, very smooth just the way the auto should be.
Lexus Australia has no TSB for a fix and just say the car drives normal and is designed to have better fuel economy. $105,000.00 car that changes gear rougher then my 17 year old Mitsubishi.
Lexus Australia has no TSB for a fix and just say the car drives normal and is designed to have better fuel economy. $105,000.00 car that changes gear rougher then my 17 year old Mitsubishi.
09-04-17, 12:01 PM
#525
My car's hesitation is still the same. I drive in Sport mode all the time now, rarely any other mode. It bothers me b/c I've taken my car back twice and the same tech said he did the battery disconnect both times and not once did I have to put my preferences back ie nag, radio etc. Should I do this myself? I read at other times that the negative cable must be disconnected at least 10 min then re-connected. Is this stil needed to help this car perform better? TIA