1993 Nissan 300ZX Car won't start

Do below

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 in away from ground have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,cap and rotor /distributor pick-up coil, ignition control module, ECM,Ignitor camshaft and crankshaft sensors and computer. Note: If it doesn't apply disregard it

Will give that a try....let you know how it turns out.

I tried everything even replaced the Camshaft angle sensor. I checked ecu was get codes 13 and 21 resolved codes and I'm down to a 55. But the car still won't start I cleaned the plugs to the PTU and I am under the belief that it's a bad unit

Are you getting the correct fuel pressure and injectors are pulsing and a blue snapping spark? If so check the valve timing.