05 DE with newly installed Z1 plenum spacer. Kinda a weird one to me but when the car is fully warmed up and I go to shift in the 3-4K range the rpms will blip up about 200 rpms twice before falling back down to the next gear. This has only happened after the plenum install and I have a 14 lb flywheel so it’s not hanging due to heavy flywheel. Heat soak maybe? I’ve checked for leaks, performed idle relearn and ecu reset and still does it. It idles perfect and runs great just curious if anyone has an idea what is causing it. Thanks for your time.

 

Did you seal both sides of all gaskets with RTV? Re-torque to 48 inch pounds?

 

Are you supposed to use RTV on the plenum gaskets? I thought those were dry gaskets? But as for the torque yes I did.

 

When I assembled mine the 1st time I had huge vacuum leaks even with clean surfaces.(I used a gauge to measure). Dismantled and sealed all gaskets, re-assembled. Problem gone.
You did actually change the volume of air in the plenum so if you want it to be perfect you should finish your air flow mods and UpRev reflash. I'll let others chime in with their experiences.

 

That was my thought on just finishing up mods and going for tune. I’ll look into if it is leaks though. Thank you for your experience I appreciate it.

 

The slow way to check for leaks is spraying brake cleaner everywhere (smells like roses), the quick way is to buy/borrow a vacuum gauge. GL!