When climbing prolonged uphills (not necessarily stiff), the engine starts burning a lot of oil and the power drops significantly.
I've noticed that if I make the climb on high RPM (~5k) this problem rarely happens, while on lower RPM (~3k) it happens every time.
What could be the cause of this? The model's Alfa Romeo 146 '97 with a 1.6 T.Spark 16V engine
EDIT: Besides the performance drop when this occurs, i also notice white smoke coming out of the exhaust.