Echo Audiofire 12 delay after a few minutes

[halobend]

OSX Yosemite
2.2 Ghz i7 - 16 GB RAM
Protools 11
MACBOOK PRO

Using the Echo Audiofire 12 on the firewire bus I have one track playing and another track armed so I can listen before I record the second track. After a few minutes I hear a slight click and all of the sudden I have a delay in the track I'm recording...as if trying to record with over 512 samples. It works fine on 64 samples until this click. I'm not even recording to the drive at this point. I WAS using an external USB3 drive but tried using a thunderbolt external drive but I'm still having the same problem. Granted, the situation is getting better because I had lots of clicks and pops before disabling anything to do with networking including on the firewire bus. I have to restart the laptop before I can try again. This problem happens over and over between the 3-5 minute mark. Any ideas???