[THE NEW GUY]

Yes, I checked all the connectors and resistances... all OK.
I already had the two new O2 sensor so I decided to change it: 30% of the problem was solved but still not the same car.... May be you was right and I should not change it, but I had to start somewhere. Decided to swap the MAF with the one on my outback: problem solved completelly. At lunch time will clear mem on the ecu and look for new stored codes. I'll let you know.