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1977 280Z Stuttering

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A lot of issues can come from modification and air leaks. 1st has there been any mods to the EFI or any other engine system?  I dont recall a detail picture of the engine bay, it may help spot something out of the ordinary. 

as ZH mentioned your fuel pressure is too high for idle, that could be a FPR thing (defect or lack of vacuum), or a pluged return line, or a massive loss of vacuum, in which case the engine would run like poo.

as far as the 0 pressure that is the way the system works, the fuel pump only runs when the engine is cranking or running. if you just turn the key to "on" but the engine is not running the pump will stay off. Its to prevent fuel from feeding a fire incase of a malfunction. 

A simple smoke of the intake system will find leaks. also a vacuum reading would be good, you should see around 15-18 inHg on a warmed up engine at idle. Vacuum leaks show up most when idling. Smoke out the system and look for leaks. Its very easy get a cheap cigar, plug up the front of the AFM, blow smoke into the intake manifold thru the brake boost port (attach a rubber hose and blow smoke there). watch out for smoke. 

I am assuming the idle adjustment screw works and the rest of the system is intact. 


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