Car has been running great, then all of a sudden I go to start and get these codes. Engine cranked and cranked and did not fire.

Turn the key off then attempted to restart and it fired right up. I understand that DTC16 is Opti-Low res pulse, DTC18 is injector circuit and DTC51 is PCM programming.


Car is running fine now.
Was this just a wierd fluke?

 

I would chalk it up as weird fluke cuz mine did the EXACT same thing
the other day and everything on my Z is brand friggin new . Mine also
threw 16 , 51 , 18 codes . I just reset the PCM and all is fine again

 

Check all your battery and ground connections.