You probably have a bad injector or you need to hard wire your ptu sub harness. Hard to say though because you need to fill out your profile. You really need to find a z specific shop and not go to the dealer unless you know a Z enthusiast works there. Most techs do not know anything about the Z32 and most of the older techs that know about them don't want to touch them. They are just worried about how many 30k services they will get that day.