Hi Metacom, yes, I have already performed a vacuum test and had no leaks (I was pretty proud of myself on that! :)
I just checked again the codes and it seems that it is throwing a "Error 11" (Crankshaft Position Sensor Circuit) !!! Thank god... at least that narrows it down a bit. I know that the wire-harness is good (since it has been replaced in the past) and the connectors are clean because I inspected them last week. Very likely either the CAS is failing -OR- the timing belt is slipping. I do have a second CAS that I can try but I'll take things apart tomorrow to inspect the timing belt.
Unfortunately I don't have a secondary good ECU... it could be the ECU (that would be something to look at after the Timing Belt inspection and the CAS replacement). I will keep you posted! Thanks again.