Younus was unbeaten on 76 at lunch as the tourists moved to within 83 of their hosts' first-innings total in a session which yielded just 48 runs for the loss of two further wickets.
Pakistan resumed on 163 for three, with Younus and Misbah-ul-Haq having steadied the ship following the loss of three wickets on day two.
And steady was the best that could be said of the early exchanges as five consecutive maidens set the tone.
By the time Misbah perished for 33 off 120 balls, caught at slip while driving at Brian Vitori to end a partnership of 86, only 19 runs had been added in nearly an hour's play.
New man Asad Shafiq kept the pace stately, though Younus did claim boundaries in consecutive overs, most pleasingly off a leg-stump half-volley bowled by Tendai Chatara.
Chatara then bowled Shafiq for 10 with a ball that moved in, leaving Pakistan still some way short of Zimbabwe's 294.