Car runs fine when first start up then after aprox 5mins cylinder number 5 dies on 1990 Nissan 300ZX

And has no reasponse at all Have changed coil packs and plugs and no change what could be causing this.

Asked by for the 1990 Nissan 300ZX
2 answers
You are missing 'what' #5 is missing 'when' #5 is missing....if you figure this out,, problem solved! Let a mechanic help you out...hands-on.
Got milk........er , I mean , fuel? Weak injector? Expensive guess, or follow suggestion #1. Might save a lot of time money and aggravation!