oldred

Maybe there is an oil/knock link? In other threads, people have sworn by using genuine Toyota 0W-20 synthetic oil to cure hesitation issues. Didn’t help me though.

Striker223

Well low RPM in high gear in a 4500ish LB car with a relatively weak low end 4.6 engine perhaps falls into the category of high load?

I am mostly just thinking at this point since I don't have a 460 I can experiment on.

All I know is that there is for certain an oil spec designed to counter this issue in smaller highly stressed engines that are common these days. I personally believe that the 1UR is weak enough down low it may fall into a similar boat, if I had my way the car would have a supercharged 6.0L engine of some sort

Doublebase

The part where you ask...have you heard of low load super knock? I have certainly experienced that in other brands. Yes.

Low speed pre ignition (LSPI): a somewhat common thing if you’re using poor quality fuel or even oil, is something seen on direct injection cars (mostly earlier model direct injection cars, I’d say). I felt it on occasion on my LS460, and I certainly felt it on my 2018 Chevy Silverado. On the Silverado forums we called it “fish biting”, because it felt like what it feels like when a fish is biting your line. That sort of quick pull/hesitation and then a snap as it releases. Almost like quick consecutive hiccups.

But the right after an oil change, for maybe a week/300 miles? Someone mentioned the oil tracking through the PCV system, where it’s introduced into the intake and burned...I’m not sure I get why that would cause that mostly AFTER an oil change (and then go away). Perhaps something in the oil causes it to combust prematurely in the cylinders, but to have it stop shortly after? That doesn’t make sense to me. There’s the idea of the valve guides, but why would a new oil change effect that? It would happen randomly all the time (if that makes sense). But it maybe it doesn’t really stop, maybe people are more hypersensitive to it after an oil change because they noticed after an oil change once? That type of thing, maybe?

The fact that so many experience this directly AFTER an oil change - and it lasts for only around 300 miles - tells me something in this engine...somewhere...the oil system itself has some sort of flaw that creates enough of an issue to active a knock sensor. Something small...something maybe that causes a slight aeration temporarily at some section, or something, that causes timing to be pulled at low speeds after an oil change. And I have NO IDEA what that is. It drives me crazy.

Striker223

If someone is willing to install an oil accumulator we can rule some stuff out......

lwphat66

Do you think this issue could have something to do with the cam oil control solenoid valves and/or screens and maybe even the small oil passages within the valve covers/top end? Perhaps dirty oil, tiny air bubbles sometimes inherent with oil/filter changes, improper oil viscosity used over a period of time? Since 2009, my '07 hasn't ever exhibited any negative performance issues after an oil/filter change, and she has been using either 0W-20 or 5W-20. I also like to make sure that gas pedal is floored at least twice pretty much whenever I drive, and furthermore, almost every time I'm on the highway she goes up to at least 100.

7milesout

Mine has never experienced after oil change hesitation. And I rarely floor it, and don't think I have ever had it over 85 mph. Maybe not even 85 mph. So maybe right foot practices are not a contributing factor...

mdpresco

I remember this topic from this thread. Around post #78. “Roadfrog”, who lives in Canada, used Toyota Oil System Cleaner which seemed to cure his hesitation problem. I could not find it in the US. The local Toyota dealer said they could not get it.

Striker223

Perhaps, my 430 didn't like my initial ownership since it started using real synthetic and I'm very hard on it. It cleaned stuff off enough inside that it caused an issue with the VVT I fixed but in the end there was enough crap inside from 200k miles before me that engine died. Not really an issue if people aren't stupid with the oil changes but......

I plan on a 13+ 460 with less than 75k miles to avoid as much prior owner stupidly as possible since I will fully utilize the engine. Only car I have that I don't would probably be the Jeep since it's a pure utility car

lwphat66

Great to hear you haven't had any adverse effects from babying your 460. Like you, I drive mine like it's a limo but more like the Transporter's ride service. <BFG>

Striker223

I have a 460 now, mine doesn't have the hesitation issue but I'll keep reporting back my findings of using 0w-30 oil in place of the XX20 weight stuff and if that changes anything.

lwphat66

Now that you own one with 130k miles on the clock, are you planning anything preemptive, in the way of oil/fuel additive or cleaning, before beginning use of the 0w-30? And which specific oil have you decided on? My car was on a Mobil 1 5w-20 diet, however, after I installed the Red Bullets last NOV I switched to Royal Purple 0w-20.

Striker223

Yes I'm doing all maintenance and valve covers/high pressure pump seals just so I know everything is done and I can start tracking everything.

Im probably going to use Mobil 1 since that is usually on sale with a free filter, my interval is 5000-7500 miles across all cars and this one won't be any different. KCLV factor on this particular car is over 25, I've had it to limiter 5 times now without any hesitation or felt issues and it is still within 400 miles of its last oil change from the selling dealer who used 0w-20 Castrol........I may just have a car that doesn't really care.

MacroP

Another affected owner here. I've tolerated this issue for about 2.5 years in the 3 years I've had this car. I only got around 6 months (at most) of smooth driving before the issue started. Actually it never started from an oil change but certainly comes back in full after an oil change. Initially I just woke up in the morning and went for a drive and the car was bogging down terribly when I reversed out of my driveway = undriveable. Had terrible induction noise and obvious timing retardation. Anyway, like others mentioned it recovers over time however mine has never goes back to 100%. I think at best around 70% of torque in the lower revs. Down low is where it is more notable. Up high it is much better but still not perfect. Transmission changes are not smooth as they could be as well.

I did take it to Lexus about 6 months ago finally and they said it drove fine and seeing I'm in Australia there is no software update for hesitation issues. They mentioned the valves spring were replaced after a recall but I think they were confusing two separate issues this car has had. Anyway, I had explained the obvious timing retardation issue to the tech and they said the KCLV was 22 at the time and that's normal. Big thanks to oldred for posting their numbers and that graph above. Seems like high 20's or even touching 30, is more normal. I have the full premium in my fuel tank too and I haven't heard any true knocking but the car may hide this with all of its noise insulation.

So today I started looking into this deeper before committing to a replacement engine. Did an oil change (oil was around 5000km old) using thinner 0W-20 synthetic as opposed to my normal 5W-30. Checked the KCLV prior using Techstream and this was around 22.5 before changing the oil. After oil change is dropped to 12.7 on my post oil change test drive with my Techstream laptop by my side. Took around 30 minutes of driving up and down the highway to get it back to the early 20's. It was slow but was noticeably rising over the test drive which was great to see. Sitting around 23-24 now and is not going any higher it seems. At 12.7 the car was horrible to drive. At around 18 it was much better but still bogging down in low rpm acceleration. At 23-24 it is better still but still not right and the transmission is still not shifting smoothly as it could on moderate throttler I think my LS430 has better performance where on paper the 460 should blow this away. It used to when I got it 3 years ago.

Tomorrow I might change the oil to a much thicker 20W-50 or something and see how that compares in the my test drive today as more as a curiosity. This engine is stuffed so I have nothing to loose really. Also I see online that my engine ECU has had a couple of part number updates over a couple of years (software changes and no engine hardware change) that are compatible with my early engine (04/2007) so I might import one from Europe as a test. It might have more knock tolerant software onboard. Nothing to lose once again.

Boykie

Engine murderer.

Striker223

DO NOT DO THAT, the pump CAN NOT FLOW THAT WEIGHT OF OIL. You are going to starve parts since flow past a given point is going to nosedive at that weight.

You don't have an oiling issue, you have a chain issue since at higher rpm the cams all gain inertia and are able to be compensated for by the ECU vs at low speed when the out of spec chain causes the sync issues the computer has to fight with to keep everything running.