For those with a Blacker and Decker Scorpion saw you might care to split open the cover and check the tightness of the screws that hold the reciprocating arm in place and the gears in contact.
Miy saw suddenly developed a nasty rattle and the blade was flapping sideways. One of the four screws had come right out and the other three were loose. This had allowed one of the slide bushes to fall out of its slot and was broken into three pieces. Luckily an almost complete range of spares is readily available for these saws so hope to have it back in action very soon but prevention is best.
Mike