Originally Posted by kalbert24

OK, thought i'd post here as well to see if anyone can relate to this issue and suggest what we can do to get it diagnosed and fixed. Here's my situation, that sounds awfully similar to what AbeTieh is describing :

I have a 2008 LS460 (manufactured 12/2007). I bought it CPO at 9K miles in 2009 May. Have been having issues with the acceleration and gear shifting intermittently. I brought it into the dealer last year, and they performed a TSIB on it (L-SB-0033-08 Rev1: 07-08 LS 460: Hesitation on Acceleration) and that seemed to fix the problem, until recently. Since my last oil change last week, the issue i mentioned is back again, but has gotten worse.

The car is normally fine, drives well, but when this issue crops up, it behaves as though the transmission is totally fouled up. When depressing the accelerator, the gears don't shift right, i can be travelling at 30mph and trying to accelerate, i floor the accelerator, but nothing happens, and all of a sudden sometimes if there is a reaction, the RPM goes to 3500, but the car is still not speeding up (i.e. at 30+ mph). The biggest frustration in my mind was the fact that after my 20K oil change last week, i was happily driving home (20+ miles away), and the car started acting up like how i've described, only this is worse than i've ever experienced in previous times. I brought it back to the dealer the very next morning, the car was not shifting gears correctly all the way there, but 5 miles from the dealership, it started acting normally again, and a short test drive at the dealership didn't produce the issue. The tech asked me to take it back (without even performing any check on it), and i was pretty frustrated, 'cos i knew it was going to happen again. And with my luck, just as i was nearing my home (about 4 miles out), there it went again, jerking and not changing gears right, the rpms going up and down and the car not accelarating.

Originally Posted by jlawr

See post #21 in this thread. It fixed my hesitation issue.

You can also try disconnecting the negative terminal on the battery for ten minutes. Then reconnect and drive the card hard with lots of quick acceleration so the computer will re-learn your desired driving habits with less hesitation on acceleration.

Let us know how it goes.

Originally Posted by jlawr

I did have the heads replaced, but I did the computer firmware update after that.
The software update and re-training the computer is what fixed my hesitation problems.

Originally Posted by Trumpanche

Just a data point for y'all. Last month I purchased an '07 LS460 with ~95,000 miles on it from CarMax and soon after bringing it home, I was experiencing acceleration problems. The car could be jerky during stop and go traffic (which my passengers found annoying enough to complain about) and hesitate when I needed to accelerate, sometimes from a stop, but more frequently in part throttle conditions just keeping up with traffic. At first I suspected a transmission issue (felt like what I imagined a slipping torque converter might feel like), but based on these Club Lexus threads, I believed I had narrowed it down to being related to the Hesitation on Acceleration TSIB L-SB-0033-08.

I brought the car back to CarMax in the 30 day warranty period and they confirmed the issue and had it sent to Lexus to diagnose per the TSIB I handed them. The Lexus service rep told me that the car's ECU had never been updated, so they performed the update and, for the the last couple of weeks, the car has driven flawlessly. I asked the tech specifically if there was a risk that my car would need the cylinder heads replaced (I was worried that my used car warranty was only 30 days), and he assured me that their diagnostic specialist was positive that my car is not a candidate for needing that fix (I didn't press him for exactly how he knew).

I would recommend, as a layman, that if you have an '07 LS460, even if you aren't sure if you have the issue, it's probably wise to get the latest ECU programming. I have a feeling that the previous owner was living with this issue for thousands of miles, but couldn't pin-point it enough (without y'all's help) to ask the dealer about it and just suffered it. Anyway - that's my two cents!

Originally Posted by DrQuality

I will discuss my own experience regarding this issue in a separate post. But first I wanted to make my ClubLexus colleagues aware that

L-SB-0033-08 "Hesitation on Acceleration" [2008-06-06, revised 2008-12-23 & 2012-07-18]

has been OBSOLETED & SUPERSEDED by

L-SB-0122-17 "Hesitation on Acceleration and-or P2119" [2017-05-03].

I did not discover this fact either in this forum or at the NHTSA website. Rather, when I presented L-SB-0033-08 to my dealership, they eventually provided in return a copy of the superseding L-SB-0122-17.

The major differences between the two SBs, as I read them, are:

* In the 2008 SB, the repair procedure calls for first performing the ECM flash … then conditionally (ie, if the hesitation is not resolved) performing the cylinder head replacements. The SB does not specify a cause.

* In the 2017 SB, the repair procedure calls for first performing the ECM flash (at steps 2 & 3) … and then, unconditionally, performing the cylinder head replacements (at step 4). The SB specifies the cause as "inappropriate spark knock or detonation detection."

This 'inappropriate detection' phenomenon is described with further clarity & detail at https://bit.ly/3ClAjBf .

Originally Posted by DrQuality

SUMMARY OF HESITATION DISCUSSIONS & THREADS

I just spent the better part of an entire week reading & re-reading about 18 threads (some shorter & sweeter, a few quite lengthy & intense) about early-year LS460 engine hesitation issues. As a result of the many, many contributions of knowledge & experience shared within them by other ClubLexus members over the years -- thank you so very much one & all -- there is at this point a very good understanding of much of these hesitation issues.

So I thought it might be beneficial to summarize the common points of what I read into a primer and/or starting point, for others who are dealing with this issue. That is not to say my summary encompasses every owner's comment, experience or solution … but there were indeed some commonly repetitive concepts within the threads.

I will also say I found some of the discussions in the threads to be difficult reading, as they digress into some very detailed discussions of powertrain & engine mechanics. So hopefully this summary will lighten the burden of others in that regard.

First of all, it all reads as though Lexus has never really come to a complete encompassing solution to embrace all these hesitation issues & complaints. The powertrain/ECU firmware was re-calibrated/updated at least five times early-on, the parts involved in physical repair (on the rare occasions when such was done) were initially found to be inadequate (or defective) and 'updated' … and Lexus seems to have been fairly silent regarding hesitation issues of the type that specifically emerge immediately after an oil change.

One thing that has apparently made these hesitation issues especially confusing & frustrating for owners is that … there appears (to me) to be THREE different types of hesitation issues in play, each with its own symptoms, causes and solutions. So, early-on, posters were routinely talking at cross-purpose, such as

* An owner with hesitation issue #1 was being offered (inappropriate) solutions from owners who used them to resolve their hesitation issue #2.

* An owner solved hesitation issue #1, then symptoms of hesitation issue #3 would emerge … and the owner would think the 'original' problem had returned … when actually a NEW problem had emerged.

Those sorts of things. Not only confusing to the owners posting and trying to find the correct answers … but to any late-comer trying to make sense of the information in the threads.

As the discussions continued and aged over the years, it looks as though the more active posters came to well understand there were these different types of hesitation issues all going on simultaneously, each with their own cause. But for someone just arriving to these threads, trying to make sense of it all, trying to find a solution for their own hesitation issue, that might well not be clear at all. It might read more like a wide variety of various hesitation complaints, with a bunch of different suggested solutions, some of which worked some of the time, but none of which worked all of the time.

So below, I grouped together what I came to understand as the three different types of hesitation issues, the symptoms, causes and solutions. Again, it make not address every owner's comment, experience or solution, but it did seem that eventually the threads generally reached the understanding that I have described below:

(1) Delayed response (only) when demanding full/urgent acceleration. The primary symptom is that the engine, upon such demand, disengages from the transmission for 1 or 2 seconds, then re-engages the transmission, then the transmission downshifts after which the vehicle jerks into finally delivering the requested acceleration. It appears that the cause is that the vehicle sensors are falsely detecting engine noises (caused by faulty valve guides with excessive clearance) to be engine 'knocking' detonations. The ECM/PCM logic ultimately fails to resolve its attempts to retard/adjust/correct the engine timing on-the-fly via VVT (Variable Valve Timing) in order to match all the correctly & incorrectly perceived detonations. And so, not knowing what timing to deliver, it delivers instead the pause of hesitation. This phenomenon is described with further clarity & detail at https://bit.ly/3ClAjBf . It appears from owner comments that performing the ECM/PCM (ie, Electronic or Powertrain Control Module) 'flash' (ie, a firmware calibration/update) as described in 2008's Lexus Service Bulletin L-SB-033-08 was highly successful in resolving the issue. (Note that Lexus Service Bulletin L-SB-033-08 was obsoleted & superseded in 2017 by Lexus Service Bulletin L-SB-0122-17.) The ECM/PCM flash apparently alters the knock detection frequency slightly so that it omits valve guide engine noise detection. A few posters report that it took more than one ECM/PCM flash, either in-the-shop or by return-to-shop, in order for it to correctly take permanent effect. Some posters report that if the battery was disconnected too soon after the ECM/PCM flash (thereby clearing certain ECM/PCM values/parameters), the 'driver learning mode' process (that, after a battery re-connect, creates certain ECM/PCM values/parameters that are used to fine-tune engine & transmission behaviors) became corrupted and, in turn, corrupted the effectiveness of the ECM/PCM flash. In that case, it was required that either the ECM/PCM flash be repeated and/or the battery be re-disconnected to initiate a new 'driver learning mode' process.

Though it apparently was not very frequently needed, physical replacement of the cylinder heads (as also described in the Repair Procedures within the Lexus Service Bulletins) was also sometimes required, after the flash, to sufficiently delete the erroneous valve guide engine noise. Even worse, a few posters reported that the parts used to perform their cylinder head replacements were eventually found to be inadequate or defective, causing additional various failures/errors and requiring the work to be redone with an 'updated parts list.'

These Service Bulletins are NOT an official safety recall and do not enjoy any enhanced/extended powertrain warranty; out-of-warranty, the ECM/PCM flash is not that expensive at all (my Lexus dealership only charged me $74.00 for it), however the cylinder head replacement surgery would easily cost upwards of $10,000.

(2) Constant/ongoing delayed & sluggish acceleration. The primary symptoms include sluggish acceleration or 'like-in-neutral' behaviors during vehicle turns, at idle & stop lights, during braking, during stop-and-go, during a constant slower speed, upon slowly proceeding out from a full stop, during on-ramping to limited-access highways. The driver may also observe slow-but-steady increase in RPMs without delivery of directly corresponding power/torque. It appears the most common successful solution is to perform the VSR (ie, Valve Spring Replacement) as described in "Safety Recall ALE 'Valve Spring Replacement' [2010-06-10]." As an official US safety recall, there is no expiration of the VSR work at no-cost to the owner.

However, more than a few posters report that the above-mentioned ECM/PCM flash, #1 as above, had to be ALSO subsequently applied to entirely resolve the issue.

There were some comments that claimed ONLY the ECM/PCM flash had to be applied to resolve this issue … but some of those owners might not even be aware that the VSR was already applied: they might be second+ owners … and (apparently) the VSR, as a safety recall, was frequently applied automatically to vehicles arriving in service bays, perhaps without the owner being well aware of it having been done.

So, in short, first ensure the no-cost, no-expiry VSR is/was applied, then apply the ECM/PCM flash after. If still not resolved, consider #3 scenario as below.

(3) Random hesitations, typically emerging immediately after an oil change that eventually 'go away' -- until the next oil change. The primary symptom is power hesitation events that occur almost entirely at random, and of varying intensity, that initiate shortly after completing an oil change, though there may also be delayed & sluggish acceleration events as described above under (2). Most posters report that these events self-resolve after about 100-500 miles of driving, while a few report up to 1000 miles before resolution. Thanks especially to detailed explanations/discussions by posters including Devh & Roadfrog, an informal consensus has emerged that the cause is that, after the oil change, the fresh oil lifts/cleans minor varnish & sludge deposits from around the engine that then proceed to clog the VVT (Variable Valve Timing) oil strainers and interrupt proper VVT operation that is dependent upon sufficient oil pressure. Without proper VVT, the timing of the engine is 'thrown-off' and delivers hesitation. Then the problem eventually self-resolves after the detergent in the oil has had full opportunity to finish dissolving/absorbing the deposits clogging the strainers.

The random nature and intensity of these events, in part, is coming from when the strainer deposits move around somewhat at random by whatever cause, blocking then unblocking the strainers. (In one case, Caha14 reported the problem started the day after his wife drove the car; I read that to mean her differing driving style, the roads she traveled, whatever, were enough to lift and/or agitate the deposits.)

The phenomenon is apparently more pronounced when drivers migrate to synthetic oil (that tends to lift/clean such deposits) after extensive usage of conventional/mineral/dino oil (that tends to allow such deposits to accumulate). Also, the consensus seems to be that a series of synthetic oil changes will eventually lift/clean most all of the deposits out of the system and so resolve the problem on a somewhat more permanent basis.

Some posters claim this was solved by specifically using full-synthetic TGMO (ie, Toyota Genuine Motor Oil) 0w20 (as manufactured for Toyota by Exxon/Mobil). Additionally, some posters recommend use of an engine/crankcase cleaner/flusher/detergent product to be introduced immediately prior to an oil change, to aggressively lift/clean such deposits into the oil that is going to be subsequently changed out. Such products include 'Liqui Moly 2037 Pro-Line Engine Flush,' 'Rislone 100QR Engine Treatment' … and even a Toyota-branded Engine Oil System Cleaner product (apparently only ever available at Canadian dealerships and now discontinued). However my own Internet-searching revealed many, many complaints that this type of product is so aggressive that it can readily & seriously damage an engine so, personally, I will not be comfortable applying them.

Btw, dealership service advisors & technicians sometimes argued to owners that any or all these types of hesitations were being caused by 'bad' or low-octane gasoline. However, even though theoretically such fuel could indeed cause these kinds of issues, most -- but not all -- posters stated that this argument, in their own cases, ultimately revealed to be incorrect. I believe I only saw 2 or 3 posters say that their hesitation problems ended entirely after merely switching-out their source of gasoline.

Hopefully the above summary will provide other owners with the information they require … or, if they need to read the threads for additional detail, the discussions there will now be easier to comprehend.

Happy motoring!

Originally Posted by Cgw1984

stop bumping all these decade old threads with this same cut and paste crap

Originally Posted by lwphat66

I AGREE! No need bombarding the forum with the same post 10+ times. Pick one thread and go with it; better yet, start your own thread on the subject so it can be date/time stamped and left to members to decide on its relevancy/importance in relation to similar threads that ended several years ago. Thanks for your help in not further convoluting this forum.