Having browsed through previous threads I came across sysmptoms identical to those found on my mk1 cabrio GLi. namely running lean, fuel starvation etc. I had tried to enrich the mixture etc but to no avail. Fortunately the thread in question (got to sort this problem 2 etc) pointed me to the fuel pump which upon testing with an old mineral water bottle only delivered 200ml in 30s. replaced it with a new bosch pump (?70 GSF) and hey presto.
Saved me lots of agro as I know my WUR isn't working properly and I might of got stuck looking in the wrong place. cheers all....................