superdenso

In my car this issue is pressure related. When I change and/or check the oil the acceleration gets weird (less weird with 5w30). Further, if I change the oil I put a (royal purple) fuel treatment in the tank. And I refrain from checking the oil because the hesi' will resurface if the dipstick is pulled. I even ask the dealer to leave the stick alone during service. I use 0w30 or 5w30 without exception. Also, the transmission fluid is changed once a year.

This is not to say that someone else's ideas don't work. But it is a description of my experience with the LS.

mdpresco

While having an alignment completed on my 2007, I mentioned to my service advisor about the hesitation. He reviewed my service history and noted my car's engine ECM had not been updated from a 2008 service bulletin. A month or so later I had the ECM updated. I can't say the hesitation problem is 100% fixed but it really helped a lot.

After the last oil change there was one hesitation on acceleration episode. But just that one. I test it each time I drive but it has not stumbled again. Has your ECM been updated?

vegasgs400

iTrader: (3)

is Toyota Engine Oil System Cleaner only available in Canada? cos i dont see any U.S. toyota dealerships carry this cleaner! does anyone know where can i get some?

roadfrog

That's what members here have been saying. I don't understand why. Like anything though, I would think one could get some if they're persistent or resourceful enough. Amazon or Ebay perhaps? As I said before though, I would try Rislone first and then go from there.

mogbert

How about disabling the knock sensors? I'm thinking I figure out the resistance of the "normal" range of the sensor and disable it with a resistor. I guess this would be a last case resort before rebuilding the engine.

DavidinCT

My 2007 is long out of warranty now. I also deal with some hesitation issues on my car. I have Toyota Techstream and it does show their is a calibration due for my car(with out a Toyota account and a correct adapter, I cant install myself), the last one according to the history was in 2008. So I want to try to get this update to see if he helps a little.

Riddle me this, if I walk/call a stealer, How much just getting the software updated in my car will cost ?

or does someone have access to the newest calibration for a 2007 LS460L and I'll pick up the $100 adapter and do it myself ?

Yes, it is possible to do them yourself but, those $15 Techstream kits on ebay wont be able to program the ECM but, the $90-150 ones (some models) can (did a lot of homework here)

roadfrog

I would imagine they'd charge an hour labor. Do you get any service done from your dealer? If so and it requires hooking up to Techstream (trans fluid change or brake fluid change), perhaps they'd do it for free since they've already hooked you up to it.

UDel

Lubro Moly has a engine cleaner that sounds very similar to the Toyota Engine Cleaner if you can't get the Toyota cleaner, you put it in right before a oil change, run it for a little while, then empty the old oil.

mogbert

Dealer charged me $180 for the re-flash. It didn't fix the problem.

GFXdznr

I too have read this entire thread. Since purchasing my '07 off of my dad last month, I have experienced this a couple of times. The oil was changed a little over 1,000 miles ago with 0W-20 from a Lexus dealership.

One other random thought I had while reading all the threads, although it may not pertain to this specific issue would be the MAF sensor. Has anyone ever had trouble with that on the LS model? My wife has an '01 GS430 and I have replaced that sensor a couple times already. Her vehicle will periodically have no power from a stop and on occasion has no downshift what-so-ever if trying to hard accelerate on the highway. I have noticed that every time I clean the sensor, the lack of throttle response goes away. We have also looked at the throttle position sensor and accelorator pedal position sensor, replacing the TPS.

I have only encountered the lack of acceleration on the LS after having slowed down from a cruising speed to near a stop (~10mph) before trying to accelerate again and coming out of a turn after a fairly quick deceleration. Sometimes I wonder if the sensor is either downright dirty or needs replaced. Other times I wonder if it's just the 8-speed and the vehicle having a hard time adjusting and finding the proper gear. Or is it an oil issue? Although having over 1,000 miles on the most recent change, seems like that would not be the case. I'm interested to learn more on this topic as well and hoping others may more recent feedback on it.

GB10

I have been experiencing these issues for the last 3-4 months now on a 90,000m 2007 LS460, with the problems becoming gradually more persistent. Reading through all the comments here, I thought a simple oil change would be a worthwhile shot, so completed a standard drain and refill using TGMO 0-20W, but after enduring a week of the now familiar gutless performance I can conclude this procedure has made no difference whatsoever.

The next stage of my plan is to establish what version of firmware the vehicle is currently running; with it being a 2007 vintage I’m hoping there is a newer version available, but I know I am going to be in for a battle convincing my dealer that more than one version of the firmware exists. Could anyone first advise how I can establish the firmware version which is currently running (I have Techstream) and confirm the most up to date firmware version that would be available? I’m hoping if I can quote specifics and TSB numbers they can’t dismiss my enquiry quite as easily.

I really don’t want to move the car on but feel as if this is my only option if the firmware upgrade does not work; I simply cannot justify the huge cost to strip the top of the engine and rebuild as I imagine the cost would be more than half the cost of the car. Current performance is not only painful but dangerous.

Is it possible to move/adjust/disconnect the knock sensors? If this is possible I would be very grateful to hear further details as the car is always run on 99 RON fuel so I would not be too concerned about an ACTUAL detonation scenario.

Thanks!

mdpresco

I had my ECM reflash completed on 3/9/16. TSB LSB003308. I don't feel the car stumbling anymore! The mileage was 81,014. It now has about 101,000. The tech said the first reflash was not successful and had to perform it again. I was at the dealer about 3 hours. The charge was $100 + tax.

DavidinCT

Thanks. I might have to check this one out... If anything I cant see it making it any worse...

Wish I had access to the calibrations for these cars. The adapter for "techstream lite" is about $85 and you can perform ECM updates with it, you just need the calabration for it.

Just wondering, if I could access the files I need and I would spend the $85 on it so I can do them again..

hfahmy

I think you have to login to lexus database from techstream to get the most recent ecu update files and caliberation, not 100% sure though. Only dealers and authorized service centers will have access to this database

GB10

Thanks for this information but as I expected my dealer is less than interested, insisting they cannot find any trace of the TSB number quoted on their system, nor do they have any knowledge of the described fault being commonly experienced. I am based in the UK but would have thought the service bulletin numbers would be the same regardless of geographical location, or at least searchable from one region to another?? I will try the same approach again with another dealer but expect a very similar response....

Does anybody have any experience with the disconnection or modification of the knock sensors? Would the introduction of an appropriately rated resistor in place of the sensor convince the car all is well?