You can download TunerPro software from [ www.tunerpro.net ] and get corresponding definition file for the 300zx from the same site. Start the software, open the rom dump and pick the definition file. It will break out the k-value from the dump and show you the values. It should be 288 for the stock 370cc injectors. If the k-value isn't 288, you've got the wrong custom rom for your injectors. There's a pop-up in the software to show you the values it should be set for each type of injector by cc.