Thank you for your reply. That was the first thing I asked the technician who came to check the TV and he said my ventilation is more than enough.
Let me tell you how the cabient is:
The back of the cabient is not solid it has many circular 4 inch holes. There is another 3-4 inch between the wall and back of the cabient. The space between the back of the TV and the back of the cabient is 9 inch.
Then there is 3 inch space on the left and 3 inches on the right side.
There is another 12 inches space from the upper side of the TV until the upper end of the cabient.
So the TV has enough space on all sides. Even the technician who brought the TV said my setup would give the TV better ventilation from the back than mounting it on the wall.
Whenever the TV is on the air conditioner in that room is on too. Touching the metal stand or the back of the tv shows how cool it is when it is switched on even for long hours.
The fault is still unknown, I just hope it is not the panel because it is hard to look for another good TV. I don't want a LED TV. Plasma choices are limited and this TV suits my needs more than any other plasma TV.
Hopefully I will know in a week of time what needs to be done.