MikeC4w

this problem if defenitly not injectors. When you are stoped it is fine. It only "bucks" or "hesitates" when you slow down to about 10MPH to make a turn or for a light that then turns green & then you step on it.
From what i understand NOW the Transmission is in the wrong gear to re acccelerate.......
LEXUS has some issues lately that they have not had in the past....... I hope it is not a sign of getting to large or taking what they do for for granted!!!!!!!

Horta

Grand

I'm on vacation right now but when I get back i will look t that service and see what else was doing. I saw injectors but may NOT be correct. I remember them telling my somthing was dirty and needed cleaning. I do remember my first service complaining about the throttle hesistation/jerk, then a service was done and its been gone ever sence.

MikeC4w

i got my transmission reprogramed yesterday morning. I would say the difference is like night & day...........It is as smooth as my 01 ls was, now

ihparker

I had the trnsmission reprogram a week ago and at first it was perfectly smmoth. Today I noticed that the problem was back.

Mandingo

Hmmm, I had mine done 2 weeks ago and it is still better. Note that it didn't eliminate the twitchy tip-in problem entirely (as I said at the time), but it is significantly better than it was and it has transformed the car.

Anyone else have opinions on the software change?

asleep

Can someone explain the fix and what effect it has on throttle response? Is the throttle response "slower" after the software upgrade? Is there a bigger delay between pressing the pedal and the car moving forward? Or does this do the opposite and fix a hesistation problem after pressing the throttle? Thanks.

Mandingo

I think it simply changes the shift points - the software has a model of engine rpm's, throttle position (and rate of change), road speed (and other items such as ECM setting) and uses these to determine when to change up or down a gear.

This map has apparently been changed with the new software and it means that the car is more likely to be in the appropriate gear when you press the pedal.

Slow speed turns, pick up from 10mph coast all appear to been signfiicantly better - press the pedal, the car accelerates - no mess no fuss.

The old problem seemed to be that you pressed the pedal and the car thought it needed to change gear - that's where some of the hesitation came from - it was changing gear at EXACTLY the wrong time. I think it also had problems with being in too low a gear which made the car jerky - if you've ever tried to drive a manual car around in 1st gear you'll recognize it's almost impossible to feather the throttle and drive smoothly, the gearing is just too low and results in herky-jerky progress.

That's my 0.02 anyway - inappropriate gear changes and staying in one gear too low too much of the time. They may have tuned it that way to improve acceleration numbers - I wouldn't be surprised if the new software adds a few tenths of a second to some benchmarks. A worthwhile trade off in my mind.

LexoRoller

I'm curious. I bought an 04 three months ago, great car except for this issue. I was attempting to make a left turn on a busy 4 way blvd, traffic was almost bumper to bumper oncoming, and it was taking forever it seemed. I had a small opportunity when there was finally about a 4 car length gap in oncoming to turn left.

I knew with 320 ft lbs or torque that I had the power to make it, rolling at around 10mph, so I pressed the accelerator about halfway and cut it sharply left. The RPM's went up but the LS barely moved. I barely made it out of the intersection and then LATER came a surge of power. Um... my grandkids were strapped in the back seat! I KNOW, don't judge me please (I wasn't aware of this issue, then).

Anyway, I really need to fix this after that scare. But these threads concerning the TSIB adjustment are from 2004. If I take my LS430 in to a Lexus service dept. now to have this done here in 2013, will there be a cost involved?