I also have an Alfa 159 1.9 JTS three years old, 30,000 miles.
I have the "Have engine checked" message for a month now, car is obviously in a limp mode as it barely accelerates.
The guys who inspected the car said it is a stretched timing chain that needs to be replaced. As the same motor is used by Opel, their colleagues from Opel Garage told them that this seems to be a production fault by the manufacturer.
I am wondering if Alfa are not liable to replace the chain for free even though the guarantee hs expired. Besides, I had issues with the car as it was going off, if I did not wait for it to get warm for a minute or so in the morning. The official Alfa Service in Sofia Bulgaria inspected it then and said there was no problem with the car whatsoever - I should have used other gas station. This statement is a joke, of course, they just did not want to perform the necessary job.....