Nissan Repair: CEL, defective coil, faulty readings

Question
QUESTION: Hello and thank you for your time. I have a 97 maxima with 176,000 miles. Recently I had my mechanic change the valve cover gaskets,replace the IACV and install new plugs. He then calls me and says he has to have a locksmith come out because one of his mechanics broke off the key in the ignition. That gets taken care of ,but my airbag light was then flashing. Found a internet site where I could reset that and thought everything was okay. He then tells me that it started running a little rough. Put his code reader on and it said #
5 is misfiring.Check to make sure it was on tight,but it still was a problem...Swapped it with  another coil pack on the engine(I believe #2) and it showed #2 was bad. So he determined that it was a bad coil pack. He Replaced that coil pack and he said it ran/runs fine. However he got anot CEL that read 02 sensor and also knock sensor problem. So he is thinking bad 02 sensor and changes it out. I had changed all 3 02 sensors out within the last year myself. Then he calls me and says that the 02 was bad  but now gets a P1320 code along with p0325 code. Any ideas on how to proceed from here. He says the car runs fine....When you replace one coil pack do you have to replace the other 5 also ? I just don't want him to just keep replacing things without finding the root of the problem. I'm not sure ,but I think that p0325(knock sensor)code is showing up because of the other code has triggered it. Is this something that I will have to take to a nissan specialist mechanic ? Thanks again for your time.
Tim

ANSWER: Hi Tim -

I would not do any more replacements yet.

If the car is running fine, have the codes erased and then see if it returns. The misfiring can cause faulty readings, so it is important to have the codes cleared, and see if it returns.

If the codes do return, please note how quickly it took to return, right away, a few days, or weeks?

It is OK to just change the one defective coil pack.

Let me know
aloha
calvin

---------- FOLLOW-UP ----------

QUESTION: Hi Calvin,
I forgot to mention that with that p1320 code it also read   
" distibutor interupted "
don't know if that helps or not
Thanks
Tim

Answer
Hi Tim -

I just asked a question on your other post.
The ignition module (which is the 1320 code) is located in the distributor, so it makes sense. So the vehicle is running OK? Even when engine is heated up? That is when the ignition module fails the most.

Thanks
Aloha
calvin