"Jacopo" > schreef in bericht
...
> It was dry, but covered with low clouds, low pressure, about 70-75%
humidity
> and 27°C.
> The air filter was changed with the oil @ 31000km. The car has now
33100km.
>

BAD abient circumstances for fine power output!
Very low oxygen % due to combination of temp. en air pressure.
Could surely be the (a) reason.
High air pressure and low(er) temp is perfect.
--
Ciao from Holland
AlfistaGJ (Gert-Jan)
Alfa red 156 SW 1.8 Madeno tuned (2000)
Golden Montreal (1973/4)