idle issues there are 2 sections. These are basic things that need to be looked at for the Z. Every little bit helps with this car. Get dielectric grease and connector contact cleaner and systematically clean and fill as many connectors you can get at. Add a ground net system see Tech section here at TT. Ohm the injectors thay should be 10 to 14 ohms. Ohm readings are lower when engine cool that is the reason for the range. My Z reads about 11 when cold and 1bout 13 when hot.