Nissan Repair: 99 Maxima PO1320, mass airflow sensor, bosch platinum

Question
I replaced the knock sensor on my brothers 1999 nissan maxima V6. Before clearing the codes I read PO325 (knock Sensor) and PO1320 (ignition coil fault). As he drove away he said the SEL came back on. The next day he said he had a no start problem. Engine will not start now. I have not read the codes but strongly suspect that PO1320 is back. A new knock sensor would not cause a no start. I have read forums and they talk about replacing the coils but all the coils have recently been replaced with new. Others point to the ECM, any ideas what this can be?

Answer
Tony,

Without the new codes I would only be guessing here.  But, I would first check the code and then the fuel pressure to make sure he is getting pressure.  Also, Nissan's are known for having strange things happen with the mass airflow sensor and they will go out and never let you know by throwing a code.  The only real way to diagnose is to use a digital volt ohm meter and follow the procedure for touching the appropriate pins.  Use a Haynes Manual for the procedure and diagrams.  Other causes could be a vacuum line has come off or there is a massive intake leak like the intake hose is sucking air that is not being metered by the mass airflow sensor.  Check the air intake leading from the MAF to the throttle body.  Also, if Bosch Platinum plugs were used they might wet out and cause a no spark condition.  Use NGK or Nippondenso plugs.