First-half goals from Ashley Barnes, Jamie Mackie, Alan Judge and Marcel Seip were more than enough to see off any threat the Sky Blues may have posed to the Greens' relegation survival.
The Pilgrims opened their account on the quarter-hour mark courtesy of Barnes, who claimed the final touch at close range to Gary Sawyer's cut-back, although it may have been that goalkeeper Keiren Westwood got the fatal final touch.
Westwood had done well to keep out a header from his own defender Scott Dann, following a pinpoint free-kick from Paul Gallagher, but merely succeeded in parrying the ball on to Sawyer.
The Greens continued pressing forward and were rewarded for their efforts ten minutes later.
Man-of-the-match Judge delivered a long cross into the box intended for the head of Barnes but, despite Westwood's attempts, his subsequent failure to clear was punished by Mackie, who slotted the loose ball home from the edge of the box.
The cheers of the Home Park faithful were in full force again just a minute later courtesy of some gallant individual work from Judge.
The Irish midfielder, like Gallagher, on loan from Blackburn Rovers, took full advantage of being left unmarked outside the box and blasted into the roof of Coventry's net from 25 yards to further Westwood's woes.
The first half was rounded out close to the interval by Seip after the Dutchman leapt over his marker to latch on to Gallagher's corner and notch Argyle's fourth.
The second half was quieter, but the Pilgrims were denied extending their lead to close to the end of the match.
Substitute goalkeeper Andy Marshall, who came on for the injured Westwood just after the interval, reacted quickest to Carl Fletcher's headed corner and parried the midfielder's effort off the line.