Where about's in Bristol are you scrumpy? Want to meet up so you can compare it to mine?
That is the best idea before spending any money whatsoever...meet up with a fellow V6 owner, and bring a screwdriver! Swap Maf sensors for five minutes, and see if there is any different. That is what I'd do.
The first Alfa 156 V6 I had was exactly the same. Then after 4 weeks, the timing belt slipped on me, bending at least 17 valves. I was quoted £2000 for a rebuild, so I opted for a donor car (which was good for stripping for spares after
) and once up and running, I had exactly the same problem as before, just like you. There were days where it would come back to me, just for a short while though!
I tried so many things with my mechanic, that eventually, he just said, it has to be the Maf But I had 2, so surely not??? I went with him though, and bought a new Maf and had it delivered to my front door from a Fiat/Alfa specialist in Huddersfield, for £150 ish compared to Alfa's £240 ish, I stuck it on, and I had the biggest smile in the world ever!!!!!!!!!!!!!!!!!
I liked it before, but now I had this extra power, I was in love!