Passat 1.8T Auto - Activated Charcoal Filter Solenoid

First time site poster, not strong on car mechanics (better on bikes) bit of a long story, here goes - I have a 2001 VW which about 3 mths ago, started to judder a bit when revving/changing gears between 2-3000 revs. Being busy (ok, lazy), I did nothing about it until last week I found that the problem had got bad enough that the car wouldnt go faster than 70mph without seriously juddering. Searching around I found the below thread - https://www.vwaudiforum.co.uk/forum/s...ead.php?t=5352 which seemed to fit my symptoms and so went to clean the MAF last w/end. Opening the air filter cover, I found the pipe connecting to the charcoal filer solenoid (according to the Haynes manual, section 4A) had come off - the white connector that connects the tube to the solenoid had snapped (hmm). Bit of superglue later, revs much better now (no noticeable judders until about 4500rpm) - problem appears to have been solved. So my question is to you folks a) what does the solenoid do and b) any ideas where I can get the white plastic connector from just in case the glue doesnt hold ? Many thanks.

The solenoid that you talk about reverts excessive fuel fumes back to the tank for bresthing/environmental purposes. Haven't got a clue why it is called a charcoal filter.

Just thought I would let you all know - after doing a bit more background reading on this site , I replaced the MAF last week with a new Bosch one from Euro Car Parts (they dont save Pierburg ones anymore; much easier that I thought it would be ) and all is now well; like having a new car again. Many thanks - much appreciated.