Hi romroc,
If the AFM were a problem you'd have serious drivability problems. Your signature lists 3 Alfa's in your stable, 2 of which are V6's. If you don't already have a shop manual, I recommend that you get one. There are a couple of sites with .pdf's available for download (Milano Shop Manual). can't remember the site, but if you can't find it, I'll be glad to burn to CD for you.
Anyway, the manual has troubleshooting matrix for several common running conditions. If you break it down, it's fairly simple. keep in mind it's wintertime which can affect whether you smell fumes readily. Anyhow, you're either burning the fuel or losing it. If
burning excessive fuel, check:
1) Coolant temp sensor (mounted at thermostat assy - second from right).
Remove connector and measure resistance across both spades.
-10*C = 7 to 12 kOhm
+20*C = 2 to 3 kOhm
+80*C = 250 to 400kOhm
2) Check cold start injector - for leaking. The cold start injector (valve) is fitted at the rear of the plenum before the throttle body (behind the TPS). It's held on with two allen screws. Remove and place in a can or jar. When you turn the key to start (
without starting - which should energize the fuel pump) see if it leaks.
If
losing fuel, you have a leak somewhere - not totally improbable given the age of the vehicle and where it lives. Or, more remotely, you may have a faulty fuel level sender or gauge indicating low fuel when the condition does not exist.
Hope this helps,

ToonR