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I've been using $200 worth of cataclean religiously every 15000 miles. Basically 5 bottles to a full tank of fuel.
I experience LSPI when I add to much 90 octane non-ethanal fuel but it's still a very rare occurrence for me now. Just got my oil changed this morning with my usual amsoil filter and 5-30 oil. Drove to Illinois and back today (300 miles) no problems, no hesitations. 95°F ambient air temp a/c on and all 385 ponies in my control.
Also note worthy is ive been using tribo-tex with stellar results my motor is legitimately feels smoother. The direct injection tick is quieter now since the application a few thousand miles ago.
So bit of an update to my hesitation issue. Has been an interesting challenge, a lot of learning and have had some good success so far. More testing to come though.
I have put the thicker 20W-50 because here in Australia that on the list of accepted viscosities in the Lexus owner's manual. Other colder markets perhaps not. It appears to not make a difference but more testing needed.
What I have done is change the engine ECU to a slightly later version (by only a matter of months). My car is a May 2007 and Lexus changed the ECU part number in July 2007 which means the engine calibration has changed and I wondered what changed as no engine hardware changed. Transmission ECU never changed though. I bought two of these later ECUs (with the same part number) and both have different 'calibrations' on them when using Techstream. One is UK spec (which I imported) and the other is local Aus spec. Both run the engine fine after syncing the immobilizer (30 minute process). I have been flipping back and forth between my original ECU and the later UK and Aus spec ECUs. The two later ECU perform the same (*) and that is to say they greatly solve my hesitation issue. The difference is massive. I have most of the missing power back. I have been testing driving (a lot) with my laptop using Techstream by my side - recording the KCLV and other parameters. Before I could not the KCLV above 24 (on the highway) and around town it would fluctuate but get no more than 22 sometime dropping below 20 and you could easily tell the power loss and the induction noise of the timing being retarded. With the later ECU - I'm seeing the KCLV level out around 30 and the missing power is back, transmission shifts are silky smooth, and the induction noise mostly gone. It's not perfect, however. Under very high acceleration there is still a little hesitation/jerkiness and the KCLV drops down a few points for only a few seconds before returning to the high number. Under low to mid throttle everything is very smooth. The engine computer is clearly picking up some noise and quickly compensating under full throttle. I might have to live with that. Car is certainly a different beast now. It seems the new calibration in the later ECU address these issues so the engineers new of this issue pretty early on. I have put the old ECU back in a few times and the initial problems are repeatable. After an ECU change, the KCLV resets to around 17 and it takes around 25-30 minutes of driving to get it up to where it is happy.
It has been over 2 years since the problem started. Lexus Australia assured me there was no problem with my engine after going for a 2 min test drive and there are no engine ECU updates for my VIN. What a load of......
* - The UK spec ECU (same part number different 'calibration') drove great but flagged a "pre-crash' code which stopped Cruise control from working) but the Aus spec ECU didn't, so I stuck with using that. I suspect the UK car had different Pre-Crash options or something or didn't have the Radar Cruise option. Doesn't matter now as it's going back on Ebay.
So bit of an update to my hesitation issue. Has been an interesting challenge, a lot of learning and have had some good success so far. More testing to come though.
I have put the thicker 20W-50 because here in Australia that on the list of accepted viscosities in the Lexus owner's manual. Other colder markets perhaps not. It appears to not make a difference but more testing needed.
What I have done is change the engine ECU to a slightly later version (by only a matter of months). My car is a May 2007 and Lexus changed the ECU part number in July 2007 which means the engine calibration has changed and I wondered what changed as no engine hardware changed. Transmission ECU never changed though. I bought two of these later ECUs (with the same part number) and both have different 'calibrations' on them when using Techstream. One is UK spec (which I imported) and the other is local Aus spec. Both run the engine fine after syncing the immobilizer (30 minute process). I have been flipping back and forth between my original ECU and the later UK and Aus spec ECUs. The two later ECU perform the same (*) and that is to say they greatly solve my hesitation issue. The difference is massive. I have most of the missing power back. I have been testing driving (a lot) with my laptop using Techstream by my side - recording the KCLV and other parameters. Before I could not the KCLV above 24 (on the highway) and around town it would fluctuate but get no more than 22 sometime dropping below 20 and you could easily tell the power loss and the induction noise of the timing being retarded. With the later ECU - I'm seeing the KCLV level out around 30 and the missing power is back, transmission shifts are silky smooth, and the induction noise mostly gone. It's not perfect, however. Under very high acceleration there is still a little hesitation/jerkiness and the KCLV drops down a few points for only a few seconds before returning to the high number. Under low to mid throttle everything is very smooth. The engine computer is clearly picking up some noise and quickly compensating under full throttle. I might have to live with that. Car is certainly a different beast now. It seems the new calibration in the later ECU address these issues so the engineers new of this issue pretty early on. I have put the old ECU back in a few times and the initial problems are repeatable. After an ECU change, the KCLV resets to around 17 and it takes around 25-30 minutes of driving to get it up to where it is happy.
It has been over 2 years since the problem started. Lexus Australia assured me there was no problem with my engine after going for a 2 min test drive and there are no engine ECU updates for my VIN. What a load of......
* - The UK spec ECU (same part number different 'calibration') drove great but flagged a "pre-crash' code which stopped Cruise control from working) but the Aus spec ECU didn't, so I stuck with using that. I suspect the UK car had different Pre-Crash options or something or didn't have the Radar Cruise option. Doesn't matter now as it's going back on Ebay.
Yes I know this thread is old but I’m replying for the sake of any future forum searchers.
Interesting observation. Does strongly suggest there is an ECU/knock sensor calibration issue at the heart of this issue. As an aside, Lexus New Zealand wasn’t interested in offering the ECU reflash available in other markets, even when I gave them the TSB documents others have posted here.
I have just posted this on the ISF forum where a handful of drivers have been reporting the same issue (even someone with a GSF ). Here’s what’s happening with knock feedback after an oil change.
ECU is clearly registering knock (real or otherwise) and retarding ignition timing.
It has nothing to do with the oil change,Has to be something else
This issue is certainly flagged by doing an oil change - it is easy to replicate on my car but the problem is not the oil change itself. The oil viscosity change or a second or two of oil stavation after an oil change causes the ECU to retard the timing by misinterpreting engine knock I think. Something in the heads and valve train is confusing the ECU on initial startup. My knock value goes quite low - 12 to 16 which is like driving with a blocked exhaust - takes around 30 minutes of steady highway driving for the correction value to come back up to around 28-30. It increases this value in small steps every 5 or 6 minutes and is predictable when running the datalog graph in Techstream on my laptop on the passenger seat.
Since I've changed to a later ECU I don't get the issue but putting the old ECU back into brings the issue back however I have to drop the oil top flag it. I have spent a lot of time (and money) toying with this.
Once the new oil is in for a while hesi should go away. I have decent experience with mobil1 full syn 0w20: New oil/no hesi. Is there an oil that may be 2% better verified by tests, sure. So one engine will last 1 million miles instead of 999,999 miles. Thats not worth the effort
08-07-22, 07:45 PM
). Here’s what’s happening with knock feedback after an oil change.
