Just wanted to let you know my experience.
So i have an Alfa 156 2.0 selespeed auto, year 2000.
I was getting the exact same symptoms when I was breaking, coming to a junction, etc the car would always want to cut out, then recover.
I had this problem for a couple of years and just got used to it, as I didn't have that much time ot take it to Alfa.
The last few months it got worse and worse, nearly crashed the car turning into a tight side street a few times as it actually started to stall and the power steeering cutting out.
I tried the first reccomended reset.
1. I disconnected the battery, left it for a few hours. connected it back then started the car and left it on idle for 30 minutes before setting off.
This fixed the problem straight away. However after turning it off and setting it off again it when back to the same old problem.
2. Then after nearly crashing it again, I have gone for option 2, snipping the wire behind the speedometer as described on this thread. I was desperate. at first when I started reading this thread, I thought it was drastic, but not now.
Straigth away the car is fixed, like a totally different car.
Just one side affect, the accelerator reaction is a bit sharp when you take the foot off it at lower speeds, ie when you want to slow down. But its nothing compared to nearly crashing it.
I know this has masked the problem, but my car is on 82k, and spending all that money with Alfa does not seem worth it.
As described before, it only kicks in after you go over 10mph, but its ok. I am more than happy. Sure it has masked the problem, but it does not bother me.
BTW, its the green and black wire for me and I did not disconnect the connectors form the unit. took the keys out though.
Thanks for this thread, and thanks for the suggestion and peoples posts. I am very happy.
Sorry one more.......