Hey guys,
I have had an issue which I wasn't able to resolve:
When cold starting the engine, there are loud sucking noise and unstable RPM that last about 1-3 minutes; after that, the engine runs ok.
During this phenomenon the exhaust smells somtimes like gasoline and sometimes just has a very distinct smell that I'm uncertain about how to describe it.

I have scanned the entire car vacuum hoses, air hoses, turbo hoses, heck I thought that maybe the air intake manifold is cracked or something, but everything seems to be OK.

Throttle body has been reprogrammed and cleaned by me, nothing changed.
Vacuum pump was replaced about an year ago as a preventative measure.
Spark plugs were replaced about 10 month ago.

After using GUMOUT fuel system cleaner for 3 continuous cycles, each after 3000 miles, things have improved considerably, where now the phenomenon described above lasts during the first minutes of the car start and not all the time like it used to be.

I fear it might be a faulty fuel injector that needs a good cleaning.
Fuel mileage is as good as it has always been, about 30 miles per gallon.

Any ideas what could be wrong with the car?

As I mentioned, after the car is hot, symptoms stop.