A hesitation in an alfa can be caused by lots of different things. I wouldn't jump right out and throw a $180 fuel pump in without further investigation.
Fuel pump clues:
Listen for the pump to get noisy....a humming noise. The noise does not have to be present during the hesitation for this to indicate a possibly bad (or going bad) pump.
After driving your car for a half hour or so, check the fuel pump fuse and holder located under the package shelf behind the passenger seat. See if the fuse holder, wire etc is warm to the touch. A little bit is ok....alot indicates your pump may be drawing more current than normal.
Other than that, check normal stuff, plugs, rotor, distributor cap, sensors, air hose connections etc.
[FONT="Microsoft Sans Serif"]Don - 1984 Spider Veloce[/FONT]