If I use Smeargle's "Portrait" Poke-POWER and find "Engineer's Adjustments" in my opponent's hand, do I have to use it if I have an Energy card in my hand?
Yes, if you have an energy card and you choose Engineer's Adjustments, you have to discard the energy and draw 4 cards.
Source: PUI Rules Team (2010-12-09), PUI Rules Team (2011-03-17)

Relevant cards

Note: All applicable cards may not be listed below.
COL1_21
HGSS3_8