I had a similar problem with my P reg Mk3 8v anniversary.
You would drive along for 10 mins then it would die on you, wait 10 mins and would generally die again. Sent it to vw and they had it a week and couldnt tell me what was wrong, but i dont trust the one near me anyway.
I had the crank sensor changed by a 'friend' and he also said i had an earthing problem to from the ecu to it. Didnt seem to be the case. It did run, but not like before. it also hit a rev limiter at 5000 rpm. Very strange. So went to an auto electrician and he replaced the hall sender sensor on the distributor.
Runs betterthan before now, havent had any problems since
