I'm on my phone so I hope this works. When I picked up my car after having an oil change, I had no power when depressing the accelerator. Lexus said I was one in gazillions that this would happen to after an oil change. They had to reprogram my car. After that it ran perfect. I suspect that's your issue.

 

Yeah , a month is along time to keep experiencing it. You probably drive your car more than i do. I had my firmware on ecu updated shortly after getting my 07 in Jan. I think i did the oil before i did that update. Really odd to see that happen at all. But it did go away about a week after the oil change. After the ecu update i think it ran better smoother and faster pedal response.

I am doing my oil this thursday so i will report back to say if it happens again.

I just had my plugs changed and oil leaks fixed on the valve covers and fuel pump that sit on covers. The fuel pump gaskets were leaking oil on the drivers side. And the plug gaskets leaked too causing the plugs to get very oily.

 

Again, a well-documented issue on the LS, especially earlier 460s, with an official service bulletin that begins with an ECU calibration software update (and contains other potential steps) that can fix the problem (worked like a charm on my '08). As stated, this "fix" hasn't worked in 100% of cases, and many owners do report hesitation strictly after an oil change (especially when done with non-Toyota oil -- I'll let roadfrog take it from here, given his experiments :-) ).

 

After reading about this I was actually afraid to change my oil last year when I got the car. I used Mobil 1 5-30. The dreaded hesitation never happened so maybe I'm one of the lucky ones.

 

What was the issue that Roadfrog knows? I vaguely remember it. Was it the viscosity of the oil and the knock-mode kicking in due to the much more slippery oil? Tends to happen when thicker old oil gets replaced with newer, low viscosity oil (i.e., after oil changes)?

Maybe they put in some really slippery oil, which is causing the engine to hear what it thinks is knocking, when in reality it's just the different type of oil that is causing some mechanical slap and retarding ignition as a result to self preserve itself and hence why it bogs down.

Maybe change the oil again to Toyota oil or whatever is recommended in the book? Cheap attempt at a fix even if it isn't the cause?

 

Still can't imagine how am oil change can cause something like this. Maybe it's regional or climate dependent? I literally live at sea level and it's in the 80's year round. Never once had this issue nor has my mechanic or SA at Lexus ever heard of it.

 

roadfrog's switch to only Toyota oil virtually eliminated the problem for him. There is plenty of more discussion on this and other theories.

The TSIB calls for, in addition to a software update (which I personally believe is always worth a shot as a starting point), new cylinder heads in certain cases. Valve guides supposedly get worn in a ways that there's noise which, to your point, triggers the knock sensors and retards timing. Again, though, based on what's been discussed here, this seems to be one of multiple possible causes; the effect does always seem to be what you state: ECU retarding ignition timing.

 

So this happens when someone switches from dealer services or uses a somewhat inferior or cheap oil that in turns damages the motor somehow?

 

If this problem results from using engine oil with wrong specs, I suspect it is a broader problem that afflicts many high performance engines. That said, the OP's issue with a sudden loss of power a few weeks after changing oil at a discount chain cannot be explained by oil quality alone. There must be some other issue with his engine.

 

I agree with your skepticism. My car has never exhibited this issue. But many on here have. It is really strange. There's enough reporting the same thing for it to *seem* to be more than a coincidence. I myself, think that the problem is not due to the change of oil itself, that there is something else that is happening coincidentally during the service. I haven't the foggiest what it could be. Because draining the oil out should not lead to a loss of build up in some area of the engine, and to have to build that back up after oil replacement. Because if so, it would happen every day, after the vehicle sits overnight and the oil drains to the sump. Anyway, this is not likely the best thread to bring up the details.

 

I'll chime in with my experience:

When I purchased my '08, the dealer had just done an oil change. Car ran great and after about 4k miles, I decided to change my oil and filter. I had assumed that all oil changes prior to mine had been done with synthetic (keep this mind as I progress with this post). I purchased a couple gallons of Pennzoil Ultimate 5W20 synthetic that was on sale and was seen as a top-tier oil at BITOG. After the oil change, I took the car to work and after a few miles, I tried to merge onto the freeway and immediately noticed the car wasn't responding to throttle input. When I say "not responding", I mean literally no response at all. It was as though the accelerator pedal was disconnected. It was scary. I did not see any SES lights come on or anything, so I assumed that it was an electrical glitch in the "fly by wire" system. The problem went away shortly after. On my way home, I experienced the same thing, this time making a left turn against traffic. This nearly caused me heart failure as I had oncoming traffic bearing down on me. Again, problem went away and then disappeared shortly after, (a few hundred miles and a couple of weeks) and for the remainder of the OCI. Several months later, it was time for another oil change. I purchased Valvoline 5w30 synthetic and did another oil change. Took the family out for dinner and on the way home, I tried to accelerate from a light and got almost no response from the throttle. Pedal to the floor....nothing. Part throttle....nada. This happened several more times and that brought me to doing a Google search for "hesitation after an oil change" and was shocked at how many results came up.

There did not seem to be any fixes of note. So I decided after some research, to try a bottle of Rislone Engine Oil Treatment and added it to the existing oil. The problem subsided a lot but was still there for a few hundred miles and weeks before going away altogether. I decided at that point to approach my local Toyota dealer. He was a car nut like me and owned a Lexus. He showed me a product they carried called, "Toyota Engine Oil System Cleaner". On the back of the bottle, it stated that it was specifically designed to clean the VVT-I system. He advised me to use the TGMO 0W20 and the cleaner, and I figured by this point that it was worth a shot. I added the cleaner to the crankcase with the old oil, ran it for 15 minutes at idle according to directions, and then drained the oil. I filled the crankcase with the TGMO oil and held my breath. That was the last time I ever experienced any hesitation (about two years).

This is where the discussions here at CL ensued. One member who I respect, had a vast knowledge with the VVT-I system. He summized that the problem I experienced may have had something to do with switching from dino to synthetic oil. This is where my earlier comment relates to my assuming that previous oil changes were done with synthetic. I had a printout of all services done by the dealer which indicated 5w30 being used. He quickly pointed out that the oil was likely not a synthetic. Hence, my switching to a synthetic may have cleaned the oil system so well that it may have loosened small amounts of carbon/sludge, which clogged the very fine mesh screening in the VVT-I system. Exacerbated even more by the TGMO cleaner.

Long story short"ish", I have not had a problem again after numerous oil changes. I recently (and with a little fear), decided to try non TGMO oil. I went with a heavier viscosity 5W30 Castrol synthetic as an experiment to see if oil consumption would go down. Again, no hesitation issues.

Many of us here are 100% certain that hesitation after an oil change is not a myth. If you Google "hesitation after oil change", you will see Lexus topping the list and other car brands have experienced it as well. Regardless, I'm so relieved that this issue has gone away. It was dangerous and ruined an otherwise glorious ownership experience.

ECU programming will not cure this issue. The ECU does not know that you've done an oil change. It may cure other hesitation issues, but I don;t believe those issues are as severe as the ones experienced in this case. We weren't taking minor hesitation, but SEVERE, prolonged and unresponsive throttle input.

 

There you are! Thanks for the refresher, very helpful.

To your last point... I don't know what actual parameters the ECU calibration update changes and of course agree that the ECU has no clue about oil changes. As I've mentioned elsewhere, by 2011 (when my ECU was updated), Lexus was already on its fifth version. This is why I always suggest it as a first step, as the car does behave noticeably better with it (all else being equal).

Having said that, I hear you; if you have scary stuff like what you describe happening, the software update won't fix it. What I do find curious is that whatever the source(s) of the problem is (are), the problem manifests itself similarly (retarded timing), but the severity and duration can vary dramatically. In essence, I had a few close calls merging (which made me push for the update when it was less-known, and dealers were hesitant to do it [no pun intended], given problems with updates on other cars like the ES330), but you are right, I never had my foot to the floor with the car not doing anything.

Definitely not a myth... I keep hearing about it at the dealership, even in cases when they use Toyota 0W20.

 

Ok, I am sorry for saying myth! Clearly, I don't have the history on this site to know about previous posts on this issue, nor have I ever come across any report elsewhere about this purported link. The engine hesitation is real, and obviously scary when it happens in inopportune moments. I was not questioning that, merely the connection to changing oil. I certainly hope I never experience this situation.

As you have both said, the problem occurs randomly, independent of whether TGMO, 0W or 5W oils were used, regardless of what oil was in the case previously. I am sure this issue has been discussed a lot, so folks may have identified other factors too. Maybe it is most common in the Toyota VVTi engines, and no one else cares. On the other hand, maybe it is so random that it is hard to pin it on any one factor to recommend a fix.

 

Just changed my oil to Pennzoil Ultra Platinum 0-20 see what happens over the next few days.

 

I can tell you from experience, having my oil changed at Lexus caused my car to have absolutely no power on acceleration. As I posted on the thread I created on the subject, I picked up my car and half way home I punched it and nothing happened. I pulled over, called Lexus and they said bring it back. The had to upgrade some program which took me roughly another 30 minutes. They told me this rarely happens and I was just a lucky guy! The worst of it for me, other than loss of time, was they had just washed my car, Had there been no issues, I'd have been home long before it rained.