Just a quick note, I'm not swapping for a Weber. You might think that is the best thing to do, fine, but Pierburgs can work and I'm trying to get mine too.
So I gave my car to a local classic car mechanic (non-specialist) to do a cam-belt change on my Scirocco, as it was a bit much for me to do at the side of the road while I don't have a garage just now. I asked them to do a coolant change while they were at it.
They then phone me a couple of days later to ask 'was the car was struggling to idle before?'.
Up until now, my car has run pretty much perfectly. Perhaps a touch of overrun on a hot day, but that's about it.
By the time I get there, they've tried their hardest, but they just can't figure out the thing, it's just about idling, but revs constantly moving around +/- 150 rpm, and idle that was a tad too low on warm-up (~1000rpm) and far too high at temperature (about 1500rpm).
I took the car home, can't figure out what's wrong myself, so I took the carb off and replaced all the vacuum lines and gaskets. I refitted everything carefully, autochoke lined up with its marks etc, but its pretty much unchanged. I've watched the carb as it warms up and the choke slowly closes, so I'm sure the autochoke is operational.
It's also clearly running rich, you can tell from the smell, it's literally spitting it out the exhaust, and fuel economy is down at least a third.
Does anyone who has cracked the pierburg have an inkling to what this could be?
TL:DR It's running rich and revs are jumping around, idle not quite right either, what could this be.
...I haven't even considered it's not the carb, but open to suggestions there too, but I can't see what would have triggered such a dramatic change