Ok, so I like so many others had the annoying rpm spike problem. And like many others it was only sometimes but mostly during the cold. And again like many others I blamed it on the Bovs and tried countless different types.
I acutally have a tial bov on order to replace my synapse now thinking that might fix it. Well im proud to say I found my problem. Throttle Body SEALS. Since ive heard milspec and many other companys say that 80-90% of 8/9s with over 20k miles on it will have bad TB seals, it leads me to believe that this would be the problem for so many. And the fact that the rpm spike happens more during the cold would make sense because as we all know most seals dont SEAL to well in the cold. But seal better in the warmth.
Also as most of the guys here probably know a TB seal boost leak is not exactly easy to find. Specially for those that dont know about this common problem.
I was also having lean Afrs at idle which was fixed when the TB seals were. it also cured my horrible BOV flutter. And also my boost leak obviously.

So in short if you have Rpm spike and its considerably bad or just a little do yourself a favor and change your TB seals before you go any further. Although these little bastards should be changed out with the Milspecs as soon as you get your Evo IMO.

Hope this helps anyone and everyone with this annoying problem.

 

heres a great how to if u want direction from here. It's a very easy replacement IMO. JUst take ur time and DON'T remove that black film inside the TB. Even tho it looks like black filth I can assure u it's NOT. Its there to help seal ur Tb butterfly plate when it closes. Again do not remove the film. If u don't believe me search it and someone did a good write up on that as Well.

https://www.evolutionm.net/forums/sh...d.php?t=220264