surging boost

[Dan Simoes]

Peter and I swapped cars at the s-car fest.  My car has a noticeable
surging, with a pair of distinct boost peaks, at around 15 and 18psi
(Lehman stage 1).  Any wisdom or BTDT?  My O2 sensor was replaced and I
will check it tonight with vagcom.

We also have both noticed a fuel smell after shutting off our cars,
around the gas flap area of the car.  In Peter's case, he also has
noticed that his gas cap no longer whooshes when he opens it.  Mine used
to, but when I filled up on Saturday, it did not.