I had the same problem and was advised to change the power save settings to off.
It appears to have worked.best of luck
I have a new Panasonic LCD TV Model TX-L32ET5B (In the UK). In some programmes in scenes with dark lighting the picture fluctuates between dark and very dark to the point where you can not see much. This only seems to happen with dimmly lit scenes, in HD as well as standard definition. The shop tried a new TV but the same happened (This however was seen by the technician from a recording of the problem I had made on a DVD recorder). The shop took this up with Panasonic and they say it is not a fault but the way their new models work trying to display a perfect black! They also say that all makes of LCD TV will display the same problem. If I watch these problem programmes on the computer the pictures display perfectly. Any thoughts please?