A week after being thumped 5-0 at West Ham, the Pilgrims notched up a second 3-0 victory in a row, with captain Paul Wotton and substitute Dexter Blackstock scoring in consecutive games and Scott Taylor netting his first goal for the club.
Crewe, who were eighth in the Championship at the turn of the year, have now failed to win in eight matches since Dean Ashton departed for Norwich and are now just two points above Plymouth.
Their cause was not helped when centre-back Stephen Foster was sent off just before half-time, but Argyle will not care about their opponents' woes after coming through a sticky patch of their own.
Wotton netted the opener midway through the first half after Crewe goalkeeper Clayton Ince, who had been at fault for the goal Alex conceded in their 1-1 midweek draw at home to Reading, made a hash of an attempt to punch out Paul Connolly's cross.
Akos Buzsaky returned the ball from the left flank, Nick Chadwick knocked it down and Wotton swept it left-footed past Ince.
Foster was red-carded after dragging down Chadwick just outside the box with the former Everton man in the clear.
Southampton striker Blackstock, who has one more game left of his month's loan from St Mary's, came on in place of Micky Evans with half an hour to go and made an immediate impact.
Chadwick made his goal, latching on to Steve Adams' headed clearance and drawing out the defence to create space for Blackstock to place the ball past Ince from the edge of the penalty area.
Taylor rounded off a fine afternoon by scoring his first goal since his Christmas transfer from Blackpool, sniffing out a point-blank chance after a neat move between Wotton and Bjarni Gudjonsson and a scrappy shot by Hasney Aljofree which he turned in.