I actually fear Everton more than Arsenal at the moment for 4th place.
The reason? After an abysmal opening 6 weeks to the season, the quartet of Howard, Yobo, Lescott and Jagielka have all remembered how to defend properly again (apart from one match since then of course! ) So with them regularly keeping clean sheets again and despite having no strikers, one of their midfielders is always likely to conjour a goal from nowhere so the winning formula is back.
i do expect the way football works that they'll pick up their home form now and their away form will dip.