So I know the Z has kind of a rough idle, but this just started happening. When I am stopped, say at a light waiting, My car likes to idle at about 750 rpm, but after a few seconds of normal idle it drops to 500-600rpm. I am not modded too aggressively, and haven't done anything for about 5000 miles (motordye plenum spacer) so I am stumpped as to why it's idling this way and how to fix.

I have about 40k miles, JWT intake, motordyne plenum spacer, and that's all that would really affect the engine. any ideas? or is it just normal.

 

Mine does the same thing, I think its the stock computer trying to compensate for the mods. I cant wait to get mine tuned, it might help you to do a reset and not just by disconnecting the battery. Google Technosquare's website for instructions on how to do it. I do this once a month b/c after a while the comp puts you in granny mood and causes rough idle and loss in power.

 

Sounds like a vacuum leak.

 

so how do I take care of a vacuum leak? do you think it is a result of the plenum spacer?

 

do i need new gaskets or just retighten bolts?

 

If its a leak check all your hoses and clamps, then make sure all bolts are tight especially the TB ones. If that does not work make sure the gaskets for the plenum are in their place. I just recently installed my spacer but my Z was doing the idle thing way before that, I dont think its a leak

 

thanks reptile, I am not sure if it's a leak. Most of what I have read said a leak will cause the idle to raise. maybe I just started noticing the rough idle we have. Hmmm... i wonder if new spark plugs would help?

 

I have thought of the same thing and have bought a set, its just such a pain to get in there. I will let you know what happens when I install them.

 

2004 z idle miss with 12k miles took it in nissan dealer called thec surport they said to clean the injectors cost $200. the car under warranty why the injectors need to be clean which is not part of maintenance with 12k miles help ............

 

if it was a vacuum leak, you should get an irratic idle instead of a steady drop. basically it should move up and down.

 

perhaps you need a tuneup . check your plugs.