1.8 auto cab keeps stalling.

Hi guys. I've mention this problem before and I thought I'd got it sorted, but hey-ho, here we are again. 
I have a 1990 1.8 cabriolet auto with a Pierburg carb. 
The car starts okay - although sometimes it seems as if the key is turned for an age until she fires up. The main problem is that as soon as you drop her into 'D' from park she cuts out. In park she is fine and will rev fine, if you do manage to get her into gear without her stalling, as soon as you touch the throttle she dies again. This happens whether the engine is hot or cold. If by some miracle you get her actually driving, as soon as you slow down for a junction etc she jumps and judders about and more times than not will stall and we are back at square one. 
Also when I turn the engine off, it judders and runs on for a bit, then conks out. I can't help but think all these problems are related to one fault. Someone mentioned the 'o' ring on the manifold, but that doesn't mean a great deal to me…… Help!
Thanks

have a read of the 2e2 faq thread, check everythign top to bottom