roadfrog

So today I changed the oil on my LS. I installed a Toyota filter and used 5W20 synthetic. Last time I did this, I developed the hesitation/lack of throttle response. It went away about 2 weeks afterwards. I haven't driven the car yet today, but tomorrow on my commute I'll drive approx. 200 kms...most of it freeway.

I'll report back on whether the hesitation returns, which will once and for all, pin-point the link between the oil change service and the hesitation.

On another note, I am sending a sample of my oil to Blackstone Labs for analysis.

Fingers crossed.......

Nospinzone

I'll bet 10 doughnuts on NO.

The reason......now that you've had practice with the car you'll do a better job!

roadfrog

Jelly filled please! Yep....it's back. Noticed it ten minutes into my drive, accelerating out of a curve from 30 mph to go up a hill. throttle pressed almost to the floor before it would begin to accelerate...and very poorly at that.

WTF????!!!

Devh

Did you by any chance reset the oil reminder. I wonder if it's the oil change or the reset.

roadfrog

Yes I reset the oil and the filter minder, but I don't see that as the issue, because it's just a time and mileage counter, not an oil sensor (right?).

Devh

I don't know myself but it was speculated that the reset may also reset some of the learn features but then again it sounds like your problem shouldn't be that bad either way.
If the issue is due to the fresh oil then there might be a situation with the VVT that is oil pressure related. I know that our engine use a motor for the variable valve timing but there might be other mechanical parts that activate the valve lift duration that is oil pressure dependent like other Toyota engines.
We can speculate on any number of things but it may not be a bad idea to get a quality flush additive before your next oil change.

roadfrog

Hmmmm......I wonder if I should try the dino 5w20? I used synth the last two times.

Devh

I wouldn't and it probably doesn't matter now. If there was some baked on varnish from the dino oil that was previously used then the synthetic oil esters are in the process of cleaning it up.
This could be a good or bad thing depending on how you look at it. The new synthetic will start to clean up those deposits and distribute them into some of the vital small passages necessary for lift engagement, then after the heavy cleaning has settled then it will subside again.
I have not studied the VVT system on the Lexus so its still heavy speculation on my part.
It could also be that the deposits are occluding some passages vital for lifter lubrication and causing noisy lifters which is being picked up by the mic on the knock sensor causing it to retard timing.
Ether way I think a long term cleaning with AutoRX and a short term flush with Motul or Amsoil oil flush is warranted.

socampbell

I had the exact same issue 2 weeks ago after having the oil changed. Took it back in to the dealer along with a copy of TSIB L-SB-0033-08 which states:

Some vehicles may exhibit a hesitation on acceleration and in some cases set Diagnostic Trouble
Code (DTC) P2119 (Throttle Actuator Control Throttle Body Range/Performance). To enhance
the smoothness of acceleration the Engine Control Module/ECM (SAE term: Powertrain Control
Module/PCM) calibration has been revised.

So they reprogrammed the ECM (no cost) and it is like driving a new car. I had previously noticed hesitation from time to time since I bought the car 2 years ago but it was never so bad i looked into it. Wish I had done so a long time ago as it is now fun to drive. There are several other threads on here about this problem which pointed me to the TSIB. Good luck!

robert1408

I had the same TSIB done about 300 miles after my last oil change. I had the hesitation and power loss but it had mostly cleared up before I had it in for the TSIB. They also did the re-flash at no charge. What little hesitation it had was gone but I'm dreading the next oil change, due sometime in October. To me, the software update makes the throttle response softer (more linear) and the trans shifting better coordinated.

There is some question in this thread about cam phasing on these engines. The intake cam is varied electrically and the exhaust cam is varied using oil pressure. I read that on shutdown, the intake cam is advanced to increase valve overlap which makes the engine easier for the starter to turn.

roadfrog

I am going to do that TSIB. This driveability issue is unnacceptable even if it's only for a few hundred miles. In fact, last time in went on for more like 700 miles.

is150

iTrader: (10)

Have you tried 0w20? I thought colder climates 0w20 is recommended. 2010+ is supposed to only use 0w20.

roadfrog

I'm not in a colder climate. I live a couple of hours from Seattle....mild wet weather of the Pacific Northwest.

Nospinzone

Did you want Dunkin or Krispy Kreme!

Yikes, I can't believe this happening to you guys. I have never experienced this in my car (knock on wood).

I guess you should have the TSIB done. I wouldn't think Dino oil would make difference ......... would it?

is150

iTrader: (10)

Could still try 0w20 and see if you get the same hesitation. I had found some old threads about the same topic.