When the Alfa 2.0 JTS engine was changed from euro 3 to euro 4 specification one of the the camshafts (eper shows it as being camshaft A, not S but my italian is insufficient to know what this means) was changed (eper gives the replacement date as 16 Apr 2003); as I understand it this was to rectify the inlet carbon fouling problem.
The JTS engine relies on valve timing to re-circulate the exhaust gasses, there is no egr valve.
Quote from ItalianCar.net:
The use of stratified charge only at speeds around idle speed, however, allows the 2.0 JTS unit to use a conventional catalytic converter system. This result is also made possible by a more extensive use of exhaust gas recirculation, which reduces the production of nitrogen oxides (NOx). Because Alfa Romeo engines are fitted with variable valve timing, exhaust gas is recirculated to the intake on the 2.0 JTS directly between the intake and exhaust valves (internal EGR).
There were many other changes made at the same time, so possibly the valve timing was not the only problem. I can say however that my euro 4 2.0 JTS which has covered 127K plus miles, is very powerful indeed for a 2 litre non-turbo engine and far more powerful than my old 156 2.0 Twin Spark.