Resetting Fuel Adaptives........Do I need to?

[UncleBoost]

Drove car 88 miles to work today.
Power band has increased, its smoother and more responsive by changing the Fuel pump relay, but still cuts back and sputters after about 4-5 seconds of constant boost (Boost gauge reading about 1/8 inch into the white) Eventually the engine catches up and I can teeter the gas pedal a little bit more. Its still not right. On the brighter side, The check engine light which usually comes on after 10-30 miles of driving with the 2-3-2 code, remains dormant so far. My next trick will be checking the AMM and cleaning it. Mileage was around 22-24mpg has dropped to around 18.<---------can anyone explain how the mileage can drop by changing the fuel pump relay???
AMM?
Volvos.....Dont you just love to hatem?