Added to the fact that my idle is too low, it is also unstable. I have on my car:

APS Intercooled Twin Turbo
Crawford Plenum
ATS twin-carbon clutch
Labree testpipes
APS true dual exhaust

The car runs really strong (450whp, 10psi), but the idle is bad. I removed the Crawford Plenum and replaced it with the stock plenum, torqued to specs and with a new gasket too. I also replaced the plugs with new ones (gap 0.040'). All of this did not improve the idle. The car stalls very often. I also checked for vaccum leaks by pressurising the system and I could not find anything.

What could be other causes of an unstable idle? MAF? Crank sensor? What else?

Thanks for any feedback.

 

My other Nissan (not Z) when hot would not Idle and stall when the clutch was pushed in. It drove me nutz and was very tough to diagnose. Turned out the intake manifold gasket was bad. When it heated up would expand the manifold and cause an air leak beyond the A/F auto tunable limits. So check for leaks. Good luck!

 

I have the same thing. It stalls when hot when I push in the clutch and come to a sudden stop. If I don't push in the clutch and hit the brakes while the car is in gear I can get it not to stall. I am going to modify the trottle plate. Some people have had success with this approach.

 

I'm not sure if this applies to you but i'd like to give u this sugestion anyway. After i installed my intake manifold, one of the vacuum tubes off the intake pipe fell off since the spring holding it together came loose. I had a super rough idle, but it would drive fine.

 

what is your vaccum at idle?

 

Mine's about 19 inches of vaccuum.

 

I had a similar issue after my Turbonetics install. After reading a lot of posts, I tried to clean my maf sensor. This made no difference. I then cleaned the throttle body and got all the residue out of it. It still almost stalls some times, but the rough idle problem is a lot better.

Dave