here are my 2 cents, i have had a digijet and now a digifant on my 84,i
have a Jetta motor now, the cap. fix worked in both setups, i really think
it is how the AFM sits in engine bay getting vibrated around in the motor,
all i know is darrel boehler install a cap on the digitool , and no more
scary hickups in either setup.

my 2 cents, results may vary.