[PinkPig]

Does yours have the problem only when the engine is hot?

Mine is a 1996/N 440 1.8Si on 88k miles.

It starts and runs fine (slightly lumpy idle, but not much). Goes fine, downt he motorway at whatever speeds, but as soon as I pull up the slip road it loses power or stalls. Feels like fuel starvation, but can't be sure. Also does the same if you drive somewhere (even gently) until the engines is warm, then stop for a couple of minutes - hot restart is a bit of a nightmare. Starts runs rough, stalls, no power, then eventually goes again fine.
Today I did 25 miles up the motorway fine, then off into slow rush hour traffic and the engine ran really rough then gave up all together. 15 minutes later after it cooled down it started and drove back home fine with a bit of a flat spot around 2000rpm.

Along with your electrical issues already posted, I'm wondering if heat is something to do with the problem - in the few moments after travelling at speed to slowing down the under bonnet temperature would rise before the cooling system could catch up (fan comes on etc). This would also be true of the hot start problem I've experienced.
Not idea what might be heating up/expanding or what ever - could be an electrical connection or a vacuum tube or even the inlet manifold (a friend suggetsed this the other day after someone he knew had similar problems on a 400 series - inlet manifold gasket was a bit shot and the heat expansion was letting air in)

All thoughts - no solutions as yet....