Here's a theory:
When the coaches hit on the gameplan, we're very good. (Seriously, very good)
When the coaches miss on the gameplan, we're one of the 3 worst teams in the league. We don't have the players to make impact plays to keep us in games where the opponent is doing something we didn't practice for during the week. Also, the coaching staff is horrendous at making in-game adjustments. When something is clearly not working, they still stick with it.
It doesn't matter how much scouting you do or how much tape you watch, there will be times when you're going to be caught off guard by something the other team does on game day. When that happens to the Jets, they get blown out.
*This isn't based on anything I've actually seen (I haven't really been looking for it). Just looking for a plausible explanation as to how a team can win and lose by so many points.
There are six 4-7 teams: The Jets, Bills, Titans, Chargers, Cardinals, and Lions. The Bills Titans, Cardinals, and Lions all have one 14+ point win. The Jets and Chargers each have 3. But the Chargers have only lost by 14 once this year, and they have lost 4 games that were decided by 7 or fewer points (1 possession games). The Jets, on the other hand, have lost by at least 14 points 5 times this season.
This is actually a trend that started last year, it's just gotten worse in 2012. We play the least number of "competitive" games of any team in the NFL. After all the excitement of 2009 and 2010, 2011 and 2012 have consisted (mostly) of Sundays where the Jets blow someone out, or get blown out themselves.