When I fuel my 2001 V70 the gas pump nozzle continually kicks back so that I can only add gasoline very slowly. My mechanic noticed that cob webs had clogged the 'vent' on the pipe into the gas tank. This may be problem #1, and it may have recently returned. However, I have also observed that if I persist in adding gasoline after the pump nozzle legitimately kicks back (i.e. the tank is full), even for a few cents worth of gasoline, the emmission control warning comes on after a few miles of driving. It stays on for the first 1/4 tank.

It seems to me that this is extremely sensitive behaviour in a car. Neither ny 1998 Volvo, nor my two GM cars (or for that matter any car I've ever owned) had such sensitive behaviour on refuelling.

Is this a known problem with perhaps the geometry of the refulling line or mechanism into the gastank? What, other than filling the tank slowly (and this doesn't usually help the emmision control problem) can be done?

Thank You

Carl.