Young went down with sprained left knee with the Titans up 7-0 and Collins doubled the advantage with a 2-yard scoring pass to Bo Scaife with 8:22 left in the half.
Rob Bironas then kicked three field goals to put Tennessee (4-2) comfortably in front. Chris Johnson carried the ball 26 times for 111 yards and a score, helping lift the Titans into a tie with Indianapolis and Houston atop the AFC South.
Jaguars quarterback David Garrard also left the game with an injury, sustaining a concussion after going 7-of-12 passing for 49 yards with an interception. Trent Edwards entered and completed 14-of-24 passes for 140 yards and two interceptions for Jacksonville (3-3).
The Titans held Jaguars running back Maurice Jones-Drew to 57 yards on 17 carries.