94 Ranger Splash noise

This is a 3L manual tranny and from time to time I will be riding down the road and all of a sudden a sound like that loud buzz will come from somewhere under the dash or possibly under the hood. If I imediately shut the ingnition off and restart it goes away. The buzz sounds much like the old door bell buzz sound you would hear in old black and white movies. Also at idol it makes a whirring sound ....very odd and bothersome. Any ideas?