Hello, I recently got a 2001 gs 300 around 2 months ago and I have been fixing it up, new struts, brake pads, sensors, some interior, radiator so on and forward.

There are a few things I wish to get help with because this is my first time owning a car and working on one

1. VSC lights turns on whenever it wants, sometimes I go to work and it’s on, sometimes it’s off.
2. When I go over moderately size dip on the road, the back tires makes a rubbing sound. I think it is coming into contact with the inner fender, is it because the wheels are too big? (i just put new struts in)
3. P0125, I searched online and it gave me suggestion to change out the coolant temperature sensor (i changed both on the radiator and the engine block) and the code is still there. I am planning to change the thermostat, if it does not go away, what else should i do?
4. When I fuel up, and have the car turned on, it shakes crazy near the back seat, and when I have the car off and try to turn it on, it does not start but after 3 or so minute it struggle to turn on and runs great after, is this because of the fuel pump?

 

I've never had this problem, but a fault somewhere in the brake system is a common cause. Each wheel speed sensor has to work properly or it will trigger this fault. I'm not well versed as my car hasn't had VSC operational since I did an engine swap many years ago. Is your ABS fully functional (do you know?) and or does your ABS light come on at the same time? My ABS is fine, but the VSC doesn't work.
If the wheels are not stock, I'd assume rear tires are rubbing on the inner side of the fender lip as you suspect. Mine do when I have weight in the back and compress like on the highway, etc. Not ideal, but rolling is not recommended, as many people damage their fenders trying this on this model of car. You can change to a wheel/tire combo that fits inboard more or "cut" the inner side of the fender where the rub is happening.
Could be there's no thermostat, and or for some reason it's not operating correctly. I've never had this code, but it's possible that the coolant isn't getting warm enough. You need a way to read the coolant temp. I recommend an OBD2 Bluetooth dongle and an app like Torque to read the coolant temp value yourself and see what's up.
Bizarre. Fuel pump is under the seat in the rear on the driver's side. I'd be tempted to change the fuel pump, as this seems like perhaps the most concerning of your problems that could potentially leave you stranded. Not saying this is the problem for sure, but given the age and assuming mileage, it's plausible.

 

You should check the water pump as well, Also check the thermostat and make sure it was installed the right way. Does the fans come on? Unplug the sensor on the radiator, your fans should come on, if that happens then it's that sensor

 

Quick update if anyone had any problems,

Got checked out with the dealer, everything is fine, just a lexus thing. ABS does not come on nor does VSC OFF, just VSC.
For the rubbing, it is because the wheels from the old owner are not stock and it has crazy negative offset
The problem was with the bank 2 sensor 2 O2 sensor, 3 of wire were good but the power wire was ripped off from old owner, I just had to weld it back and it was good, code clear.
Still have not gotten to this, everything is working fine except for fueling up. Least of my problem right now since I have state inspection coming up.

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