Dear All who did reply to my previous post, I wanna thank you all for the comments;before to post here, I already brought the car to a famous local Bosch service in Italy, the owner of the B service is an old experienced man on old cars, but the engine still doesn't run at full six cylinders. He explained me that there's a rotating part (inside the I P) that was rusty (and may be ruined as well). I guess that ruined part, is something like a small crank shaft that acts the quantity of fuel per cylinder @every revolution. What is worst is that I guess that part, is no longer available...