Rubbish Idle :(

Hi eveyrone, I'm having some problems with the idling on my cabby, has anyone got any ideas?

It seems to idle a bit lumpily when standing, either when cold or warm. Maybe it's a bit worse when warm actually. Anyway, eventually it just conks out. Once when this happened, it seemed that the engine carried on for a bit after it stalled and made a horrible whining noise before stopping!

It had a really rusty filler neck when I got it, which I've now replaced, but havent looked into the tank yet. I did however get the strongest magnet in the world from ebay and stick it to the underside of the tank. The fuel filter seems a bit mucky- no obvious lumps of rust, but just a bit dark. Also I've got the pieburg 2e2 carb. I notice that when it conks out it seems to rev lower and lower until it just stops.

This may be related, but when the cars accelerating under load in 1st/2nd I hear a bit of a vibrating fizzing sound. Also, I've had the car garaged and drove it for the first time for a few months this weekend. I'm wanting to use it as my daily driver now really, so I'd like to make sure it's nothing massivley serious.

Maybe this is more than one issue, I know I need to inspect the tank, but maybe some of the symptoms point to other things??

Cheers!