Code P0333, Knock sensor 2 circuit high voltage?

Here is the code definition:

Error code P0333 is a diagnostic trouble code (DTC) that indicates a problem with the "Knock Sensor 2 Circuit High Input (Bank 2)".

Can I ask how the engine sounds when running? Can you please shoot a quick video with your phone so I can hear the noise? That way I can tell for sure what's going on. You can upload it here with your response.

This can mean that the powertrain control module (PCM) has detected a high voltage input signal from the knock sensor 2 circuit on bank 2. This could be caused by a faulty knock sensor, damaged wiring or connections in the knock sensor circuit, or a problem with the PCM itself. I would replace the sensor first, which is the most common. You can test the sensor by putting an OHMS meter on ground and the center of the sensor. Then rap on the engine near the sensor and you should get a reading. Also check the electrical connector which you can get a pigtail for and wire it in. Please let us know what happens.

Hello, they might be twisted together like that to keep the wires from getting interference from the Starter motor which is a high current flow component or from an ignition source. The torque spec on these is very important, service info says only 17ft lbs. About the twisting of the wires, you might check the other knock sensor to see if those wires are twisted as well. The Knock sensor produces its own AC voltage when it reads or experiences any vibration or engine knock. So that might be why they are twisted together, Although I have never seen a pair of wires to one being twisted. But check the other bank and see if they are twisted, that will answer your question. I'll post the wiring diagram, so you have the colors of the other sensor. But even tapping a wrench on the engine block will get a voltage signal from them. They are a Piezo Electric crystal that will produce a varying AC sinewave.

This vehicle does have a Brake Booster Pump, which is controlled by a brake booster pump relay, there is also a brake booster vacuum sensor on the booster. The Brake Pedal Position sensor on this is actually like a APP sensor for the gas pedal, it has 2 Potentiometers, one receives a 5vRef and sends a signal to the ECM and the other gets its 5vRef and signals to the BCM. So, it's a bit of a different setup, newer technology.
The hesitation you are feeling might be a carbon build up issue in the Intake ports and on the back of the Intake valves, this being a GDI high pressure direct injection engine, they have major carbon build up on the intake valves because there are no fuel injectors in the Intake manifold anymore. With conventional fuel injectors they spray into the intake and help to clean the intake valves. But with direct injection the fuel injectors spray directly into the cylinder, so GDI systems need to have a intake valve cleaning done manually. It's usually a walnut blasting of the intake valves. Thats the best way to get them cleaned up. If it's never been done on this vehicle, with that mileage it's way overdue. It will eventually lead to cylinder misfire codes.
Another thing to watch for is the high-pressure fuel data PIDs on a scan tool. These GDI systems can run 800 to 2000psi fuel pressure. So, if the "Desired" vs the "Actual" fuel pressure is too low or high, just things to watch for. But it will usually set a code if the fuel pressure sensors are reading out of spec. But valve cleaning is something that should be done with regular major services. Personally, I'm not a fan of these systems just because of this issue alone. But it's something that most manufacturers are incorporating now. So, it will still have a low-pressure pump in the tank, but also a high-pressure pump driven by a camshaft. With steel lines running to the fuel rails that are a onetime use. Here are some pictures of what happens to the intake valves. The fuel injector tips also start to get carbon build up on them too, restricting flow.

On the steering issue does the vehicle have electronic power steering? Where an electric motor is used to assist with steering. You would notice a large electric motor incorporated into the steering rack. And a lack of power steering pump and fluid reservoir. Some newer vehicles use a steering angle sensor along with the conventional fluid power steering system. Since the system works with the ABS(EBCM) system, you might want to have a full system scan done on the vehicle to see if there are any codes stored in any other modules besides the ECM. It might be that the steering angle sensor needs to be calibrated, Vehicle systems now are becoming so complex with a module for every little thing. Most of the time we need to rely on the built-in diagnostics to give us a direction, with either a code or something noticeable in live data.
When you did your smoke test did you have the air intake boot off to where you could see the throttle plates? It sounds like the engine stumbles under a load, being that it is happening in gear, and when coming to a stop (so deacceleration) the fuel injectors are cut off until you come to an idle again. This is to cut down on emissions. If you have a capable scan tool. You can see if it has a fuel injector balance test in special functions. Being that this is a GDI system, never mess around with the high-pressure fuel pump or fuel rail even with the vehicle off, it will still hold something around 800psi with the engine off. So, testing with a scan tool is the safest way to begin. If you have a bore scope you can pull a couple spark plugs and look into the cylinders, you should be able to see the tip of the fuel injector and possibly the intake valves if they happen to be open on that cylinder. Check for any carbon build up on the end of the fuel injectors,
GM has quite a few bulletins out on fuel system treatment and cleaning. Diagrams 3, 4 are together, and 5, 6. Both are TSBs on the fuel system treatment. There are about 14 or 15 TSBs just on the fuel system alone.

Under scan tool data, you can monitor the Long- and Short-Term Fuel Trims to see what the ECM is doing during the hesitation or stumble. If you're feeling it in the vehicle there will be something in the live engine data that should stick out. I'm not sure what scan tool you have, but I don't think you're dealing with a vacuum leak, I do see in the wiring diagrams this vehicle has a Map sensor and a MAF, although the MAF is labelled under Multifunctional Intake Air Sensor which is attached to the air filter housing and will measure incoming air like a MAF but this one has an Intake air temp sensor, humidity sensor, absolute pressure sensor(before the throttle plates), Mass Air flow reading. So, this sensor you would want to look at the (grams per second) the engine is taking in at idle (in Park) and then at 2500rpm as well under a load. This being a 3.6-liter engine, at idle in Park, you should have roughly 3.6 grams per second of air flow (g/s). And it will increase greatly at higher rpms.
If you can do a wide-open throttle run, (on some street where you won't get a pulled over) and record the peak RPM and the Mass air flow reading at that RPM we can calculate a Volumetric Efficiency test. The test instructions are in the 7th diagram, and the 8th is an example of a tests results. It's a great test, but the correct data has to be collected to do it. But I do think the issue is going to be carbon build up, especially if the vehicle has never had the intake valves cleaned and it's at 150,000 for mileage now.