I have had my 94 GXE for less than a week. This morning it started sputtering when i gave it gas. at traffic lights the idle drops down and it sputters and knocks. at high rpms it is better.
from reading the other threads it sounds like the AAC valve..
What does aac stand for? and does anybody think this is it
I might sound stupid but i'm just learning about nissans.because my last car was a corvette (P-O-S)

 

AAC = Auxilary Air Control

I believe this is only for the air conditioning. When you turn on the air conditioning the AAC is actuated and it raises the idle about 100rpm when under a load. (This has nothing to do with your problem )

It could be alot of things, first try using some injector cleaner.

 

check you plug wires, i had the same problems you have and i hate a cylinder that wasnt hitting.

 

The idle-up solenoid valve adjusts the idle when theres heavy load, like A/C. I think the AAC regulates air flow once the engine/coolant has warmed up.

 

Thats right, the AAC is for cold start-ups, It's a wax pellet that expands as the car comes up to operating temperature. When the car is really cold the pellet has contracted and allows more air flow to raise the idle so the car will warm up, it slowly expands and the idle comes down to normal when the engine is at operating temperature. So this isn't your problem either.

Although just to note: The idle air control valve and the AAC should be cleaned with Carbuator cleaner b/c carbon deposits build up in there and restrict air flow (And in the worst case parts can totally clog or possibly seeze). When I cleaned mine the idle rose 200rpm!