High idle RPM after long trips
 

My 617.912 Diesel engine seem to have developed a very strange behaviour after long trips - the idle speed goes up to 1000 rpm instead of normal 600-700 rpm. If I put it in 1st gear and move a bit the rpm speed goes down to it's normal value then it goes up again.

Does anyone know what causes this very odd behaviour to a 3000cmc 617.912 Diesel engine?

Does it also get 'the shakes' after a long trip?

No. This engine runs perfectly otherwise (new injectors, new injection pump, complete engine rebuilt 8.000 Km ago).

The only problem would be this odd idle rpm change.

Well I have no ideas. But hopefully the bump from this reply will cause the right person to see your post.