At 06:44 PM 6/15/2012, Steven Johnson wrote:
>had the shudder since.    I smile every time I think about it
>because I did many long freeway drives where it more than likely
>would have had the syndrome..

In addition to the ostensible purpose of filtering out high-frequency
vane flutter from intake-tract resonance, either one has the entirely
salubrious quality of filtering out dropouts from a tired carbon
plate inside the AFM, extending the practical AFM life by years in some cases.

I've tested the two (cap/pigtail) with a sweep generator and scope
and their behavior as low-pass filters is essentially the same, as
well as my leaky sieve can remember now.  I'm sure the person who
devised the fix put the pigtail on a sweep generator, looked at it
and said "that's all it does?  Why did they bother with an active
circuit?" and calculated the value of cap that would approximate the
same response.  I've suggested to Bus Depot that they have some
pigtails made up with the cap built in.  That would be a plug-in
solution for the masses, if they could get the connectors cheaply enough.

Yours,
David