In my case it is not a vacuum leak. I currently have the Fuel Trim Malfunction codes for both banks and it is in the shop now. The mechanic verified it is not a vacuum leak. His suspicion is that it is a bad Air Mass Meter because the voltage readings are not what they should be, during an instrumented test drive. He did not have a new Air Mass meter to verify today. I will know tomorrow if this is correct.
The Air Mass Meter was replaced and it runs great, much more power. No more Fuel Trim Malfunction codes.