The Minstermen went down 3-2 at high-flying Plymouth after more defensive blunders left them trailing at the interval to strikes from Jamille Matt, Reuben Reid and a Will Boyle own goal.
York goalkeeper Scott Flinders made a smart double save to deny lively pair Reid and Matt on the quarter-hour mark but, six minutes later, the Pilgrims had forged in front when Reid beat Boyle to Graham Carey’s left-wing cross and his downward header saw Matt fire home from five yards.
Reid went on to net himself from the penalty spot, converting on the half-hour mark after Dave Winfield brought down Matt.
The Pilgrims made it 3-0 on 42 minutes as Boyle’s diving header flew past Flinders following Graham Carey’s inswinging free-kick.
York reduced the deficit on 52 minutes when Penn fired past Luke McCormick from 20 yards.
Michael Coulson then squandered an excellent chance with only McCormick to beat.
But the visitors did give their hosts a nervous finale when Summerfield converted an 86th-minute penalty after Boyle had been hauled down by Jordan Forster.
Plymouth Argyle: McCormick; Forster, Nelson, Hartley, Sawyer; Jervis, McHugh, Houghton (Tanner, 80), Carey (Wylde, 81); Matt, Reid (Boateng, 62). Unused substitutes: Mellor, Simpson, Purrington, Dorel.
York City: Flinders; Hendrie, Winfield, Boyle, Ilesanmi; Penn (Berrett, 90), Bennett (Riordan, 88), Summerfield, Coulson; Alessandra, Fewster (Oliver, 60). Unused substitutes: Ingham, Dixon, McEvoy, Galbraith.
Referee: Dean Whitestone (Plymouth)