cctaco

Hi I'm a new to this forum, Long periods of cranking needed to start it up, seems to start better if I floor the gas pedal while cranking. This is a interment issue sometimes it just start perfectly. check engine light is on, these are the error codes. using a basic Innovia 3100a code reader. P0160 o2 circuit no activity code detected (bank 2 sensor 2) P0325 Knock Sensor 1 Circuit (bank 1) Would like any help in pointing me to the right stuff to fix on it. Little history: I bought my pathfinder in 99 and it's been great. 205,000 miles with very little issues. We had a issue with the transmission shifting real hard and the od light light blinking, took it to a shop they couldn't figure it out. Researched it and found that it was a resister, easy fix and things are working better. Last week. Last week I changed the spark plugs on it, and they never had been changed since new. They where very worn out and it idles much smoother. Replaced timing belt around around 190,000 miles, water pump, all rubber coolant lines. Thermostat. Battery was week put a new one in it yesterday. Now here is my issue getting check engine light, these are the error codes. using a basic Innovia 3100a code reader. P0160 o2 circuit no activity code detected (bank 2 sensor 2) P0325 Knock Sensor 1 Circuit (bank 1) Would like any help in pointing me to the right stuff to fix on it.