Can an O2 sensor cause faulty spark plugs on driver side only when the spark plugs were just changed?

A loose O2 sensor will give a weak signal to its ECU. The ECU will then richen the mixture on that bank, possibly accounting for the plug soiling. If the vehicle is then road tested before release the subsequent faulty wiring would normally be found. Without being hands on with this particular vehicle it would be impossible to be definite about its faults or if to blame anyone. What I would say though is that if a vehicle has persistant and repetitive faults then one good way to get to bottom of things would be to run the vehicle with a data logger connected. This will give you a second by second view of any fault developing and go a long way to nailing it whilst sitting at your computer.

IMHO, O2 sensor can't cause damage. If signal is faulty - ECU must be working in safe mode. That is why your check engine lamp was light on.

But if you have bad high voltage wires (plugs - coil) then high voltage jumps through any weak points and can damage and even solder parts. It also can damage ECU and its electronic parts like condensers. I suggest you to change wires every 0.5-1 year, it is cheap but very important.

If you are getting an O2 sensor code, you really need to start at the core of the motor, and have your intake, exhaust, and head gaskets redone. O2 sensors throw codes if there is an air leak, and it could be far from the O2 sensor. A valve adjustment may also be necessary. If it's dying while you're driving down the road, that sounds like your alternator. Also if you are jumping on the highway without letting your car warm up, your spark plugs can actually shatter.

When an O2 sensor goes bad the ecu knows it and ignors it so only enextended driving period may cause the plugs to foul but certainley not in the short run . While on the other hand your injectors get + all the time from a common wire and the injections come from - that pulsates from the ecu each injector with its own wire . If these wires are shorted together or to ground (-) the injector (s) may be continuously open causing large amounts of fuel to flow into the affected cylenders and cause one side of the motor to foul while the other side works fine

The ECU will always default to a rich mix if there is faulty O2 readings.

While this can foul the plugs, dilute the oil, etc it will not cause damages while a lean mix could.

Now, cars can run without O2 sensors and the default tables, while rich, will not be rich enough to foul the plugs.

Something else happened: the readings could have been considered valid and the ECU compensated by making the mix very rich, fouling the plugs.

This can happen in a few scenarios:

• The is a leak by the exhaust manifold. Once exhaust velocity reaches a certain threshold, the leak doesn't let exhaust out, but actually sucks air in; as explained by Bernoulli's Principle.

• There is an electrical problem; an O2 sensor will have a voltage reading of less than 0.45v if there is oxygen in the exhaust stream. A faulty ground, or a short, can create this condition.

• Ignition not working on that side; the mix is not burnt and there is still plenty of oxygen left in the exhaust stream. This will foul the plugs very quickly.

• An injector stuck open; this will make the combustion fail and then you have a lean condition as well; essentially plugs that foul, don't burn the mix and then the O2 sensor reports a lean mix, so the ECU adds even more fuel.

One test you can make is to see if the car behaves differently when cold: O2 sensor readings are used only when the sensors reach their operating temperature, after a few minutes; if the car suddenly behaves differently when switching to what is called 'closed loop' (using sensors for feedback), it is an indication to look at the O2 sensors, if not look at the other options.

if you have a bad o2 sensor sending a lean signal to the ecu for one side of the engine, then yes is will drive the ECU to create a rich condition to compensate, fouling the spark plugs on that side. an exhaust leak can cause an o2 sensor to read lean, or possibly a short or bare wire in the harness, or defective o2 sensor. or perhaps it really does have a lean condition due to an intake manifold leak.