P1320, P304 codes on a 2000 Nissan Maxima - Also codes 301–312

A few times my 2000 Nissan Maxima would suddenly run very rough, and the idle became so unstable it nearly stalled out. This would clear up after about 15 minutes, when the engine would sputter, the MIL would light up, and then the engine ran smoothly again. I read a code P1320, "Distributor Signal Interrupt" each time, and at least twice it was accompanied by a P0304, "Cylinder 4 Misfire Detected". I searched the internet and found a service bulletin on this problem, implicating the ignition system for cylinder #4. The owner's manual describes how to replace the spark plug, which requires removing the ignition coil. I replaced the ignition coil and spark plug in cylinder #4, and the problem has not happened again. The total cost of the parts was $100, including a new spark plug socket wrench!

A few months before I successfully diagnosed this problem I mentioned the P1320 code to the dealer. They said all they could do for that problem was to replace all six ignition coils at a cost of more than $600. Key to this repair was identifying the specific cylinder (the P0304) code that was having the problem. Note that codes 301- 312 all indicate cylinder misfires, for cylinders 1 through 12 (dream on) respectively.

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