Digital BW, The Print

Hi All:

Epson 9600
Lyson CIS
Cone NK7 bulk
Everything reasonably low milage

I'm having severe issues with keeping ink flowing.  I'll have a 
perfect nozzle check, then moments later have no ink at all in a K 
shade.  Power cleanings help, but often additioanl cleanings are 
required.  I've tried cleaning the wiper/soaking the pad.  I've let 
it sit turned off.  I've blown a ton of ink trying to get things 
working consistently.  It's so bad I can't even calibrate the RIP.  
I can see isolated small air bubbles in the lines.  After a 
cleaning, I can see the bubbles slowly migrate back toward the 
cartridges.  I've jacked up the left side of the printer with a 
2"x4" thinking maybe ink was siphoning back and pulling air in the 
heads.

Anybody, any experinces like this or any ideas?

Thanks,  Jim