Can I switch the driver side to the passinger side? Are they the same?

Mechanic says 02 sensor needs to replaced.
How many 02 sensors are there in Toyota Sienna 2009
And what are the possibly that could be the problems?
It has 97k miles on it.
The codes that I found out was:

Any advice ?

need to replace the rear seats in my van

I have to put a blow drier to the engine for an hour before it starts, it's like it can't take the cold

Engine doesn't sound any different, nothing different about my van, just the light came on.
Oil was very very low, added oil, cleaned air filter, but light is still on? Can I reset the light by pulling the fuse out and putting it back in?

The EVAP code 440 was returned. Did a smoke test and found a plastic valve on top of the gas tank is leaking. Very hard to get to and because of the age and rust this is going to be a bigger job than it should. Cannister and other valves OK. Anyone else encounter this?

I bought the car from a nissan dealership in oklahoma last saturday 06-01-13, the car died on the highway on my way home, towed the car to a mechanic who said the engine was no good, that it knocked. Now the car starts but has a knocking sound. i called the dealership they are throwing as is clause at me. Since the car did not even serve me a day, is there any laws that protects consumers that are victims of this type of dilemma?

this is constant without the lights being turned on.
my brake lights do however work correctly.

Only after it rains or gets very damp outside...

The van is coding out with no spark or power to the fuel pump.

It is stuck in the full up position. moved smoothly then just one time stayed in that position.