Toyota 4Runner 1999 engine cranks

:oops: I have a Toyota 4 runner 1999, 109K milles, auto trans, 2 wheel drive 4 cilinder. When I start the engine, a loud noise came from the front of my car and when I try to power off the engine still jumping, even with the key out of the switch. I ran few milles and after a minute the noise stop and the car came back to normallity. Somebody can tell how I can fix the problem? :Roll: