Check VSC light on and RPM drops and shaking every 3 minutes while driving?

Tiny
KIWASABI1
  • MEMBER
  • 2007 LEXUS ES 350
  • 2.0L
  • 2WD
  • AUTOMATIC
  • 172,000 MILES
My friend's Lexus E350 is experiencing RPM drops and shaking / shuttering every 3 minutes while driving. There's a "Check VSC" light on by his gauges. There's a check engine light, but the only code is P0333 which relates to the knock sensor, which seems unrelated.

Any idea what to check and what's going on?
Saturday, July 12th, 2025 AT 3:25 PM

6 Replies

Tiny
KIWASABI1
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  • 202 POSTS
The more I'm thinking about this the more it seems like a fuel pressure issue. Fuel injectors or fuel pump. That sort of thing. The VSC and P0333 knock sensor codes are likely unrelated to red herrings.

And when it comes to issues where there's a drop in power and RPMs while driving, there are about 50 or more possible causes for that issue. I just know that when I've had issues like that in my Mitsubishi Eclipse, it has generally been fuel pump and other fuel related issues.
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Saturday, July 12th, 2025 AT 7:57 PM
Tiny
MECHTRIX
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Id say have it scanned and or diagnosed theres a bunch of things the can cause a knock to occure, but that said " The VSC light indicates a potential problem with the "vehicle stability controll" but actually the more impotant one right now would be the po333 code. It indicates a knock sensor issue on bank 2 that would be on the side where cylinder 2 is I believe on your car its under the intake manifold. It can be coused by many things one of the more serious thing would be a worn timing belt. Has it been changed . Its crucial to check them and change them at the factory recomended time intervol id say change the knock sensor roght away and youl most likely see results. And then have the belt checked for abnomal wear and replace it right away if its found to be worn out over due or defective. Hope this helps.
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Saturday, July 12th, 2025 AT 10:46 PM
Tiny
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Thank you for your detailed and helpful response.

The main issue of concern here is this drive ability issue where the car shakes and the RPMs drop every few minutes. Could that be related to either the knock sensor or VSC issue?

I used my OBD code reader, and the only stored code was the P0333 code. The "Check VSC" indicator is an internal part of the car's own computer system and does not appear on the OBD scan.
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Sunday, July 13th, 2025 AT 12:02 AM
Tiny
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Yes, these Lexus vehicles are pretty good they rarely have problems that said ". The knock sensor should be changed right away. And check the timing belt at the same time. Sounds like your engine might have other mechanical issues but it's too early to say. He knock signal can be caused by a few things like.
Bad gas
Bad timing components
Bad coil
Bad plugs
Bad knock sensor itself. Or worn internal parts or other various conditions " but" the good news is you only have the one code right now no other codes "lucky" so changing it might just solve the problem. The first step is to change it. Pretty important before other problems occure. Good luck
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Sunday, July 13th, 2025 AT 7:02 AM
Tiny
KIWASABI1
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But doesn't the P0333 knock sensor engine code seem to be properly detecting that something is wrong with the engine? I don't see why the knock sensor should automatically be replaced.
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Sunday, July 13th, 2025 AT 5:39 PM
Tiny
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This is based on the information I have is theyre anythin you might have left out? Ok so you said there was shaking every 3 mins or so right? But in between whats it doing? Is it running normal? Do you here it making sounds in the engine knocking rattling pinging marbles in a can?Is it capable of running normal in beween shaking ? So"you have more than one knock sensoer and 2 cam sensors but becuase the code indicates a problem with the the knock sensor on bank 2 sending a higher than normal signal but not the other one on bank one and no codes for cam sensors. It can mean the sensor itself is bad or its getting a super strong knock or excessive vibration inside the engin from that specific area of the engine on bank 2 where the sensor is. If the engine was bad youd be getting alot more codes from other sensors around the engine but all the other sensors on the engine are not sending codes right . And these sensors are vary sensetive it seems to be bad. That said. Theres all sorts of testing you could do on it though so if you really want to anylize it find a shop the has a bidirectional scan tool it can scan much deeper and test the sensors and othe various components to give you alot more information but since youre only are getting that code its probably gonna tell you the sensors bad . But id just change the sensor theyre cheap maybe 30 dollars or less for the part and if its bad like I suspect than the engine should run normally again good luck.
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Sunday, July 13th, 2025 AT 9:13 PM

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