So I have a 07 and I did not remove the TB to clean it or anything, it throws the 0507 code (high idle) here and there, but I've noticed even when the code is off, the rpm will stall at 1500 rpm for about 2-3 sec then drop down to 600.....help.

 

sounds like you need to do the idle air relearn

 

Been there done that, maybe I'll do all 3 of the relearns together, but it doesn't make sense to me that the idle is weird without the code being on.

 

Did the relearns fix your problem?

 

I would start by cleaning the Tb. 600 rpm is a decent normal idle for the Z, and that code is most likely not a "first trip" code.....Meaning that it's allowed to happen at least once without setting a code.