TV flickers then goes off and on and flickers again then goes off and on

What?
If your back-light Flicker; just ask your wife to look at it.
If the back light of your TV flickers;

Fault with the main power supply regulator board. Ubnormal DC voltage output from it. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and precious time.

You have answered your own question, someone needs to open it and find a loose plug or broken solder connection--if it reacts to being tapped on that is the issue- a physical problem inside.

If for example a Samsung it is in the power supply of the set--no brand or model number indicated here so that limits the scope of a possible answer.

Replace CRT NECk

Cold solder joint on the board. Time to call a TV tech..

N Sabre

1. Need Model # of set and the brand so I know if its a plasma, LCD, or CRT set keep me posted

Make sure you have the PS3 set to the correct frequency for the TV. Many cannot accept 1080p / 24fps etc.

Try different settings.

I hope this helps.

tae your tv to a w/shop tech
your tv has a dry joint or one of the active components is heating up
or a supply is varing

is there any spar, u observed inside the tv when it do like this.