It has been a wheeze-inducing ailment which has dragged Pompey to their knees since the days of Paul Hart.
Avram Grant couldn’t stumble across the answer. Neither could Steve Cotterill, Michael Appleton, Guy Whittingham or Richie Barker.
Now Andy Awford is faced with the same apparently incurable illness – Pompey’s travel sickness.
Since 2009-10, the Blues have won just 21 of their 120 away league games, a period spanning all four divisions in England.
Just as alarming, they have tasted defeat in 64 of those – a staggering 53.3 per cent of away league fixtures fulfilled.
Awford isn’t the first to be affected by this long-standing complaint, although the Fratton faithful hope he will be the last.
On Saturday the Blues head to a Tranmere Rovers side fighting for their Football League lives and currently sitting in the relegation zone.
With seven defeats in their last 10 league matches – and no victories – Mickey Adams’ team represent an opposition ripe for plucking, with the greatest of respect.
Then again this is Pompey on their away travels.
Awford’s troops have collected one win and three draws from their nine league matches away from Fratton Park so far.
In terms of points in League Two, only Carlisle (four) and Tranmere (five) – two of the bottom three teams – have a worse record.
Meanwhile, outside of the Premier League, no side has scored as few as Pompey’s three goals.
The nearest to such an unwanted statistic is 17th-placed Mansfield Town, who picked up a 1-1 draw at Fratton Park early last month.
That was one of five goals recorded by the club, which last week sacked Paul Cox as manager, although they are still 10 points clear of the relegation zone.
Even the only two teams outside the top flight not to have seized a victory from an away game this season have mustered more goals than Pompey.
League One Gillingham have grabbed six goals and suffered six defeats, while Cardiff have five in a campaign which has seen them reap five draws on their travels.
Oxford United’s Kassam Stadium represents the only venue where the Blues have won outside Fratton Park in the league this season.
That success arrived on August 23 when Craig Westcarr’s late goal secured a 1-0 win over Michael Appleton’s side.
Elsewhere, Jed Wallace’s equaliser during an impressive second half at Exeter City on the opening day gave Pompey a deserved 1-1 draw.
There were also points gained in the form of goalless draws at Hartlepool and York over successive weekends.
Currently Hartlepool are rooted to the foot of League Two and eight points adrift of safety, while the Minstermen are fifth from bottom having failed to win a home game so far.
On the flip side, only Shrewsbury Town, Plymouth Argyle and Bury have a better home record than the Blues’ 20 points.
Now this weekend attention turns to that chesty cough which just won’t go.