HDTV widescreen - Grey bars on side, not black?

What is the cable box? On my hdtv box I have a setting called tv borders with options like dark, light etc.

My Sony HDTV has the option of changing the color of the bars.

Mine switches between gray and black, as you're describing.

You must use the Sony remote control (not cable remote) to access the menu. Mine is a display option, part of a list that includes settings for sound, format and color balance.

No guarantee your Sony's the same, but it costs nothing to look.

I also get grey bars (at times) on my 42" Sony Plasma.
I actually prefer the grey bars to blackness, but instead have adjusted my eyeballs to view 1.33 in 'widezoom' mode.
I cannot control the grey bars. Sometimes they are there, sometimes not. (never on horizontal black bars as when watching a 2.35 aspect movie. just 'sometimes' when watching a 1.33 one.) (never on NTSC or digital over the air channels. Those always have black.)
Just in the video modes...
Screwy!
I love the Sony picture, but screw the controls!! or lack of!

Post this question under "Home Theatre" and you might get a few more responses.

Sometimes I get what Elizabeth desrcibes and if I toggle the channel up and down it goes away when I go back to channel I want to watch. My fathers TV does either black or grey bars thru units menu.