That the Plunge Protection Team has been called in means there is big trouble! The PPT is a real lawful entity designed to manipulate the US Stock Markets. It is officially known as the Working Group on Financial Markets (WGFM). It was created by by President Reagan’s Executive Order 12631 in 1988 following the 1987 crash. Its purpose is to lawfully prevent catastrophic market crashes. All the above factual knowledge is available from reputable sources findable via your fav search engine.
This is both good and bad news. Those short in the market could protect their positions - and if they have enough guts take long positions for a limited period. It's not my business to say when to do this, as I have no advance knowledge of the future or when the PPT will strike!
Note carefully that my language above is speculative, except that Dow and Wall Street are in big trouble. This is now common knowledge as the fall in the market has well exceeded the respected figure of 16%. If/when the PPT weighs in it'll have to be with billions and billions of US-Dollars, as loads of people are likely to set up sell orders for the next opening of the markets.
That the PPT has been called in does not mean that they have a 100% chance of moving the US markets north.
It all depends on whether they have enough to push back the deluge of selling they're likely to meet. Nobody I know, knows exactly how the PPT works. Perhaps they will get first orders, beating back all regular investors from selling or shorting. That would make sense. If they are successful, Forex pairs especially those with Yen and AUD could be affected by indirect effect. What it would mean for US-Dollar strength, is another problem.
Note also that other countries have variants of the PPT, some operating covertly.