Coventry were denied a first victory in five League One outings by Sam Kelly's late strike, as Port Vale held their guests to a 1-1 draw at Vale Park.
The Sky Blues' automatic promotion chances were dealt a serious blow by Kelly's fabulous, long-range effort in the 84th minute of the clash, which leaves Tony Mowbray's side seven points behind second-placed Walsall.
Jacob Murphy had given Coventry a first-half lead but the visitors were unable to hold on and have still not won since January 2.
Elsewhere in the division, Barnsley showed no ill-effects from losing manager Lee Johnson to Bristol City, as the Tykes beat Bury 3-0 to extend their run of League One victories to seven.
Marley Watkins scored in the 19th minute to hand Barnsley the lead before Sam Winnall's left-footed finish, after fine work in the build-up from Adam Hammill and Conor Hourihane, doubled the hosts' advantage.
Hammill added a third with 24 minutes left, firing home from Ashley Fletcher's cross, to send the Tykes within five points off the play-off places.
Finally, Fleetwood remain in the final relegation place after drawing 0-0 with Shrewsbury, who sit one point above the Cod Army in 20th position.