# Z31 wont hold RPM under 1000



## Maverick_124 (Sep 13, 2011)

so, my Z31 wont hold any RPM under 1000. i have it set to about 1300..and its freaks out most of the time..the RPM will go down to 500, shoot to 2k, then down to 1000 and bounce between 700 and 1200 and just randomly die..but i think its a simple vac leak..i do remember there being a cylinder thing on the front of the motor..i think it has to do with the Fuel..


it looks like this... http://usedzparts.com/index.php?main_page=product_info&cPath=78_26&products_id=58 but the little Vac thingy isn't curved like that.. its straight (about 1/2" long) and looks like someone bent it so it cant be used..ill get pictures one of these days


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## rogoman (Dec 16, 2004)

That is the fuel pressure regulator. The tube on top is for the vacuum control of the fuel pressure; it needs to be operating correctly which changes the fuel pressure according to the load on the engine.

The extreme idle swings is a condition called "hunting". It could be caused by a dirty air filter, a major vacuum leak in the intake system or a dirty idle air control.


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## Maverick_124 (Sep 13, 2011)

well, it does it with, or with out an air filter, but if i keep idle above 1k it holds steady..its currently set at about 1150..

its probably the air control. tho..i i just remembered seeing a hose that looked like it was cut in half...its the big (looks like 1") tube with a Y bend in it. it connects to the TB, and i don't know what else...I should look into that..


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