97' E36 328i vert queries

Hi Peoples

Im new to the forum. Good to meet you all.

I bought my first Beemer....a red 1997 E36 328i Convertible with just under 189k KM on the clock and had a major service about 4000km back at E-car somewhere in Bedfordview before I got her. Iv only owned her for about 2 months now. But since im very unfamiliar with this brand, I have a few queries.

1. Is it normal for the L/100KM gauge at the bottom to go past 39.5l/100km and hide away during idle?

-I have a feeling the beemers overfueling, on inst cons....shes usually stuck on 39.5L on idle and start up with white-ish smoke on start up. I dont smell excessive petrol fumes in the exhaust though. She also idles roughly at random moments.
-On acceleration....she BUUURRRSSS....sounds almost like a trucks air brakes.

2. Is there anyone in the South or Alberton areas that has a diagnostics machine and wont charge a small fortune?

3. Is there anyone in Alberton with the same model that I can compare mine to?

I have a few more queries but cant think of them right now. lol

Thanks for the help guys!