Exhaust fumes inside cabin when left window crack opened

[brajomobil]

It has puzzled me for couple of months why there are exhaust fumes inside cabin
When I opened left window for 10 cm. If I open window fully or open both windows
No fumes! I have searched all over forums nothing similar. Then went searching other
forums and found solution on Alfa GTV forum. It seems many Alfa GTV are suffering
from this. Bad rear bonnet rubber sealing. When you crack open left window it creates
Low air pressure in cabin (ventury effect) that sucks exhaust fumes trough bad rubber
Sealing. I have checked my sealing and it was in perfect order. Nothing fishy about it.
So I took masking tape and from outside taped over complete bonnet cracks. Went
Over a couple of miles and no exhaust fumes. Changed the lower rubber sealing,
exhaust fumes gone for good It was looking really good but it was somehow
not sealing properly.