what's up guys. so i've ran into a issue i can't figure out. My 2003 Z was idling rough so i decided to do a idle relearn and well after the procedure it started to make a very loud whistling sound that it never made until i did the reset. i uninstalled the TB to clean it and installed a new OEM nissan gasket thinking it would fix the problem but nothing. The sound itself seems to be coming around the back of the engine around the throttle body and under the plenum. My Z does have intake mods such has a Z1 5/16 spacer,motordyne iso thermal mod,stillen hi flow intake which never made the noise until now. the car is throwing a pending P0300 for some reason but im not sure if it has anything to do with noise. I have replaced the plugs, cleaned the MAF, and checked all the coils and checked the plugs for a dirty plug but they all look equal. well if anything helps i have a video of the exact noise it makes that i took.

 

You've obviously got a vacuum leak somewhere. Especially true if it gets better when you open the throttle, because vacuum drops when you do that.

 

Thanks bud. I'm guessing it's coming from one of the the gaskets I probably messed with a while back. I'll take apart the plenum and see if that changes anything,kinda sucks it just showed up out of no where.

 

Found the problem, failed motordyne thermal gasket! Thanks again for the help dcains. Mods please close.

 

Happy to help - glad you got it figured out.

 

Glad you got it sorted!

 

thank you!