Did a little more digging around online and the only thing I have found is speculation. Some people say a similar problem was fixed after changing the DISA, others have reported fixing the problem after replacing the CCV system, others have reported fixing the problem after replacing the pre-cat O2 sensor, while others have reported fixing the problem after simply cleaning the MAF. On the other hand, there are others who have tried this entire combination only to have the problem persist.

Roh, oh - not feeling good about this one...