I will try to be as descriptive as I can...

The sound I hear is similar to someone tapping their finger / fingernails on a desk maybe 2 or 3 sounds a second. It's very erratic without any sort of rythm and only happens at idle when the engine is completely warm. If I rev it even a little, it goes away. It sounds like it is coming from directly under the center of the engine (plenum area). The only mod I have is a kinetix plenum but I don't see how that would make any difference. Any ideas?

 

probably an injector, very common.

 

Huh. I could see how it would be an injector. I would hate for my Z to take up the habbits of the DSM parked next to it. Is it just an annoyance or is it a more serious problem?