Apparently a source for the "2 engines off" is the press secretary of the catholic bishop of Haarlem-Amsterdam (Netherlands):
"I clearly saw smoke coming from the engine. The plane made some loops over the Adriatic Sea." (...) Lufthansa was according to Peeters very vague about the cause of the smoke. "Something would have gone wrong in the kitchen where meals are heated. But I think there was more to it. The pilot had two of the four engines off. Therefore it seemed we were floating. Everyone held his breath. We obviously have done some prayers."
Source:
Noodlanding vliegtuig met bisschop Punt erin Archief 2011 [Actualiteit | Katholiek Nederland]