Thousands of Nissan owners have to spend a lot of money to replace the bad fuel injectors. The main symptom is higher resistance of injectors which causes injectors' failure. I have several injectors with the exactly similar problem.
I just spent a few hours to disassemble a bad one and found the reason: a pool design of the injection between the solenoid coil and the output leg. Just a spot weld is applied to this contact surface and it is very easy to be broken at the early age; which will cause higher resistance or disconnection. This is not strange that some owners reported new injectors can only last several 10k miles and had to replace.
I would like to provide some pictures to illustrate my discovery if anyone has interesting.