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This is always a controversial topic here. The best process you can do on this is to use one of the good spray in intake cleaners. If you look at the Top of your plastic intake manifold on the back there is a nipple with a rubber cap with a squeeze clamp. I confirmed with Lexus that its there for intake cleaning service solution. You can also get something like the Seafoam spray in cleaner which to tube, is inserted into the boot and sprayed in. Its been confirmed that cleaning does help and will raise and produce a High KCLV engine.
For pour in Gas tank the BK44 was rated the best to use. I do both the spray in and in tank cleaner when I do it periodically. If you do the spray in do it right before you change your oil as a little will blow by and make it into the oil.
Or you can take off the Intake manifold and do a visual like myself and one other GS owner here and know that it's worth trying to keep it clean and decarboned.
Chevron Techron is supposed to be safe and in my case came highly recommended as the only additive that a well respected mechanic, (Junior Damato, can find him with a Google search) in my area suggested anyone use in their gas tank, (No fuel injector cleaners). He had a weekly article in a local paper back in the mid 90's. I followed that and used it in all my cars up until recently. I would add it to a full tank a week before each oil change, 3-5k mi depending on which car and how long ago. I used it in a 95 Ford Taurus v6 that went for over 275k miles before I gave it to my son. I also used it on my 02 Camry v6 XLE which was at about 305k miles when I got my GS350. I never had an issue with it especially causing any codes. Perhaps your O2 sensor was on it's way out and it's just bad timing? You could try resetting the code and keep driving to see if it comes back on. Some Google searching has shown that most people don't believe that Techron use would cause an O2 code and some have reported that it has cleared an O2 code. I'll assume that you added the proper Techron/Fuel mix. They do sell 2 different size bottles. The smaller one is good for an average tank of gas but, the larger one can be used in 2 tanks or 1 large tank like in a truck. I'm also wondering how many miles are on the car and if you use quality gas. Possibly the Techron cleaned a bunch of crud out of the system and fouled the sensor and causing the code? If so, this may go away after it's burned off. Good luck!
I'll assume that you added the proper Techron/Fuel mix.
20 fl oz for the 22 gallon gas tank.
Shell 91 octane gas.
Engine light came on after about 1 tank with the Techron, before I refilled tank with gas.
I'll try resetting the codes; maybe it won't come back on..
Well, that isn't a 4th gen Lexus GS from the dash displayed and the VSC light says it has other issues. I would not see any way an appropriate amount of Techron would cause an O2 issue. Those sensors do go bad from time to time. I've replaced a few in my day. Techron is the same additive found in Chevron gasoline already and if you use Chevron premium, you wouldn't need to run Techron additive.
The TRAC OFF and Check VSC lights on can be caused from using a cheap OBD II scanner assuming that those came on after scanning the vehicle for your O2 Sensor codes. I'm not sure why but I've experienced it a few times, (Possibly every 3rd or 4th use) myself in my former Camry. The fix for that, which is separate from the O2 codes is pretty simple. Just search Youtube or Google for how to perform a Zero Point Calibration. It only takes a few minutes but you'll need a couple of paper clips and you'll have to short a couple of pins in the OBD II connector. I found this video helpful:
Well, that isn't a 4th gen Lexus GS from the dash displayed and the VSC light says it has other issues.
It's a 2005 LS430. The initial discussion was about fuel additives, and I didn't want to start a whole new discussion about that in another group when there was already a lot of good info here.
The TRAC OFF and Check VSC lights on can be caused from using a cheap OBD II scanner assuming that those came on after scanning the vehicle for your O2 Sensor codes.
The engine lights came on before I used the bluetooth OBD scanner (Torque Light mobile app). That's why I hooked it up to pull the exact codes.
I used the scanner once briefly when I bought it about a year ago: no side effects.
I also took my car to a parts store where they used their more professional scanner (wired), and confirmed the O2 sensor issue on Bank 1, Sensor 1.
12-25-21, 12:49 PM
