I have a 2005 evo with i/h/e, ets intercooler, and kelford 272 cams running 22 psi. Upon cold start up my afr's are spot on around 14.5 - 15.0, but when the engine heats up after a bit of driving i get a roaming idle sometimes going from around 12.0 to full lean, sometimes staying in the middle around 14.0-15.0. Does this sound purely like a tuning issue or are these the symptoms of a mechanical problem such as a vacuum/exhaust leak, etc? Any help would be greatly appreciated.

 

i got same problem you fix it yet? seems like after my cosworth cams it started doin it

 

First test should be a boost leak test. These cars freak out with any leaks.