I recently had the fix installed for the Check engine light recall related fuel pressure rail sensor on my 2004 S60 2.4. All of the sudden, about 1K miles later, I am having issues with lack of power when I step on the gas. At a stop light it will "Bog" down and sometimes die. When I am moving and hit the gas, I get a surging effect as the RPM's climb as if I am rapidly pumping the gas pedal.

I have been told everthing from fuel filter (BTW where is it) to fuel pump to throttle position sensor and/or O2 sensor. Anyone ever experienced this or have any thoughts?