I failed the emisson's test. I have a 97 Nissan

Those codes are for the knock sensor(325)m and the EGR valve(1400)

Well, sometimes you get lucky replacing parts, but usually its something other than the component in question.
The trouble codes are a guide as to what to test, not what to replace.
Code 325 is for the knock sensor which could be a phantom code.
Code 100 is for a bad signal from the MAF sensor which may or may not be caused by a bad sensor. It could be a vac leak too.
Code 110 is for a bad signal from the intake air temp sensor. The signal tells the computer what the temp of incoming air is to help the computer decide how rich the fuel mixture should be.
You need to get the testing procedures for each code and follow them. I would skip code 325 and start with code 110.
The fuel pump was probably a waste of money unless you checked fuel pressure before you replaced it and it was low. Same thing with the O2 sensors. Very rare if both sensors fail at the same time.

A code P0300 may mean that one or more of the following has happened:

• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Stuck/blocked EGR valve / passages
• Faulty camshaft position sensor
• Defective compute
• P1105MAP/BARO Pressure Switch Solenoid Valve
• Check and clean the MAP sensor, or replace.
• P1492EVAP Canister Purge Control/Solenoid Valve (Circuit)
• Replacing the purge solenoid will clear code P1492 This should also clear code P0300 as well.
  

P0325 NISSAN - Knock Sensor Circuit Malfunction
Possible causes- Faulty knock sensor
- Knock sensor circuit short to ground
- Knock sensor circuit short to power
- Knock sensor circuit open
- Faulty Engine Control Module (ECM)

Read more: http://engine-codes.com/p0325_nissan.html#ixzz29K4BM3th

Please go to this link for instructions.

around 300.00 -400.00 est. at dealer garage maybe little cheaper not much more

P0325 is a knock sensor. the knock sensor will not set the ses ligth

how did you fix your p0446 code?

Hi,

The two codes seem to be related. The P0325 description is knock sensor circuit malfunction and the P1320 is ignition signal - circuit malfunction.

I'll summarize and then give links on more detailed articles I found. Basically the P0325 refers to the knock sensor and associated wiring. The P1320 refers to the ignition coil and wiring. Check the sensor, coil, and associated wiring.

I found some great articles:
P0325 - http://www.obd-codes.com/p0325
P1320 - http://autorepair.about.com/library/a/1i/bl039i.htm

Good luck!