Not sure if this is a coincidence or not but,
We have 2 TDI's in our household, a 2002 Golf 5spd and a 2001 Jetta Auto.
The Golf is my wife's and doesn't use any additives and I can't be the one to monitor if she does or not, I do religiously every tank.
For the past 1 or so she has been having issues with limp mode, all the remedies have been tried to cure this (by me of course) with no avail.
Each time it craps out, I get the same code P1562 Quantity Adjuster Limit exceeded. So today I finally tore into it, and fixed some other things such as crappy connection at the inlet side of the pump/dried out hose,did the HAMMER MOD and put all new clamps on every connection.
So I too am wondering if the additives do anything for our pumps, I would say yes as I have not had a sinlge issue in 5 yrs with my Fuel System.
I say use additives everytime you fill, there aare lots out there find one you like and is good for your pump, I use PowerService white and silver jugs.
http://http://www.powerservice.com/
