Why is my radio come on for 2seconds and then go off for awhile then d

You may have a bad ignition switch — not the part that you put the key into, but the electronic module behind the key switch.

I had a Mercury Grand Marquis once, and sometimes the radio would go on and off and on and off and on and off… A coworker asked his brother, a Ford Mechanic, what it could be, and he told him the ignition switch. I bought a new one at Auto Zone for $15 and installed it, and the problem was solved. It was an easy install; and the old one had a smoky smell, as if it had been burning.