You're correct. The engineers write it and "spec" things out. Then the legal department reads it over in an effort to make sure nothing is hanging out there that could create liability issues. Been there, done that.

 

I'm just here to say I have a 09 LS 460 and the same exact thing happened to me. I immediately came on CL to see if anyone else was having the same problem and low and behold its true. This is the first oil change I had gotten since purchasing the vehicle. I am unaware as to what type of oil was used in the car prior to my ownership, however it was serviced at a Lexus dealership, so I'm going to assume they used whatever type of oil they provide during oil changes. I took my car to a reputable mechanic I've been dealing with for years and I decided to go with the Mobil 1 5w-20 synthetic. After I drove the car 40 miles from the mechanic, it drove fine with no issues. I drove to work where it sat for about 8 hours and when I got back into my car to drive off, it immediately started to drive sluggish. The usual light taps on the accelerator to get the car going wasn't even working. I tried to do a hard acceleration and the car wasn't having any of that. The tachometer was erratic and the gear selection was terrible. It threw no check engine lights. I drove about 20 miles on the highway headed home and miraculously, it started to work fine with no issues with accelerating. I took the car out today for my daily 40 mile commute to work and it drove with no issues. I don't have the slightest clue as to what's causing this to happen. To test this oil weight theory, I'll ask my mechanic to use that synthetic blend next time instead of the full synthetic and see if that curses the problem.

 

Honestly, I doubt this had anything to do with the oil change. Sounds more like a temporary gremlin elsewhere (electrical connector, spec of dirt in fuel injector, etc, etc).

 

This sounds more like a build batch issue for the 07-09 years. It can't be affecting every LS460 after a oil change or else you would have hundreds of people on this thread complaining and there would be a lawsuit by now. Toyota has to have figures out what this is by now.

 

My 2007 did it until the ECM was reflashed. Some have had their heads replaced to cure the problem.

 

Doubters not withstanding, it indeed has EVERYTHING to do with an oil change. That's how I discovered the problem existed in the first place after doing my first oil change after buying my car. All I did was Google "hesitation after oil change", and discovered this forum. Same with countless others. DevH (who used to frequent this site), had some good theories on why this was so. In my case, my hesitation occurred immediately after using synthetic oil. The previous owner may have been using conventional oil according to service records. The theory is that the synthetic cleaned the engine so well, that it may have dislodged minute particles and entered the VVT-I system causing blockages and hesitation. Eventually those particles dissolved, and the car returned to normal. This occurred after two oil changes and hasn't returned since - approximately 2 and a half years. The VVT-I system is very sensitive and also has very fine passages (something to that effect). When I approached my dealer, they sold me a bottle of "Toyota Engine Oil System Cleaner", which also mentioned the cleaning of the VVT-I system: http://www.donvalleynorthtoyota.com/...system-cleaner

 

I have Techstream (12.0.0127), can I reflash the ECM with it or is this something only a dealer can do ?

 

That is interesting, glad you got yours sorted out, it would drive me crazy if my car was doing that after every synthetic oil change, it should run better if anything after a oil change and using a good synthetic. Lubro Moly makes a good engine flush, sounds pretty similar to that Toyota Oil System Cleaner that you add and run the engine right before draining the old oil.

 

Well, let me tell you....it was VERY scary. I had just bought the car after trading in a more than troublesome BMW 7 series, thinking that I was getting into a car that would finally end the drama. I had owned the car for about 2 months and did the oil change. The hesitation LITERALLY started a mile or so afterwards. No response from the throttle whatsoever. Very dangerous. The rest of the story many are familiar with, but eventually the hesitation disappeared (about 200 miles or a few days later). That was all good until about 5 months later after my next oil change.....immediately after the oil change came the exact same symptoms and issues. And again, disappeared the same way as before. That lead me to these discussions and research.

 

That's funny you said that. I had the same thoughts as well. I was leaving a 430 and got into a 460 and was priding myself on going with the LS instead of a 7 Series all because Toyota products are supposed to be stress-free.

Silly of me not to find out from the dealership on what type of oil they used last when they serviced the vehicle, but I assumed it was synthetic and thought all the newer vehicles came standard with synthetic oil. Had I known, I would have just stuck with the conventional oil. I decided to use synthetic because its a better quality oil and it last longer than conventional oil. During my next oil change, I'll be sure to request the conventional oil instead.

My hesitation problem occurred on Thursday April 6. I stepped on the gas and there was literally no power. Even when I floored it, the engine struggled to pull ahead. I was freaking out because I thought it was tranny issues, but no check engine light came on. After driving about 10 highway miles, I floored it and the power returned.

On Tuesday April 11, it happened again. After I dropped off my Uber passengers, I pulled away and hesitation occurred again. Once I got on the highway from doing about 10 miles, no sign of the engine hesitating.

I emailed Lexus Corporate about the issue to see if they will reply with a response. Did anyone have to pay the dealership to reflash their ECM or ECU?

 

Dont worry about using synthetic. My bet is that the problem will disappear after a bit. Basically, once the superior cleaning qualities of the synthetic do their thing, the problem will not return. You could try a quality oil system cleaner first (I use Toyota's product), and the go from there. But again, I'd stick with synthetic 0W20.

 

I have had this problem for little over a year now... yes every oil change ....yes it eventually goes away but that's not ok...and I've done all my own oil changes sometimes I reset the maintenance light sometimes other times I don't... I have even tried changing the oil and not the filter... so many different variables same results I'm am an ase certified mechanic ran my own Mobil1 mechanic shop for 13 years before I sold it to valvoline. I am now a sr.network engineer I travel a lot using this car I put about 35k on my 2007 since purchased. My last resort is the dealer now I have the knocking noise with the breaks no codes or anything checked with my snapon diagnostic tool. I have owned a 7 series the a8 the a7 Cadillac all the big luxury vehicles ....although those cars have had issues none like this I like to speed and when this random (no longer random) issue occurs it's nerve wrecking and dangerous...is there anyone with a 2013+ having either of these issues I love the big Lexus and don't mind upgrading but I don't want these issues to follow. My car is a 2007 just now hit 120k bought at 7?k 1 owner. I even had 22s and thought it was maybe the wheels took those off still issues only product I have used is seafoam every 3 months.

 

So....do you use synthetic? What viscosity? Have you had the ECU reflashed on the trans or engine or both?

 

fist oil change Mobil1 0/20 then Mobil1 5/20 then regular 5/20. then synthetic blend 5/20 even tried royal purple got desperate and did Mobil1 5/30 all the same reaction. Reading this thread I just discovered the flashing of the ecu so that's next I'll just do both since I'm going to be there and have them check everything else.

 

Well, having the ECU's reflashed can't hurt, but going back and forth with your oils (synthetic to dino etc), would be the other thing I'd avoid. You could try a bottle of Rislone Engine Treatment with your next oil change like I did, before I used the Toyota product. Synthetic oils already have great cleaning qualities, but if you go back and forth to the dino oils, who knows. When I beat this problem 3 years ago, I followed a regimen that I could trace and assess. All I know is that after using the Toyota Engine Oil System Cleaner and TGMO 0W20 oil, my issue has never returned and I never had the re-flashes done.