Problems with my 1999 Mazda Millenia V6 2.5L

[IcyBob]

1999 Mazda Millenia 6 cyl 2.5L Front Wheel Drive Automatic 146000 miles

I just bought my mazda millenia 2.5L V6 last mouth. The day I bought it I knew it had problems but not this many.

Anyway, the engine was misfiring so I changed all of the spark plugs. That fixed some of the misfires. Now, P0302, Cylinder 2 is misfiring and I am also getting P0300 and I do not think it is the wires.

These are all the OBD code I am getting:
P0300 Random Miss Fire
P0302 Cylinder 2 Miss Fire
P0325 Knock Sensor 1 Circuit Malfunction (Bank I or Single Sensor)
P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input)
P1195 EGR Boost Sensor Circuit
P0170 Fuel Trim Malfunction (Bank 1)
P0173 Bank 2

My question is where is the fuel trim located.

And if you can help me with any of the above OBD codes. I will be cleaning each sensor. The only two I am worried about are the last two P0170, P0173 because I have a rough idle.

Thank you for your time.