Patrick Agyemang opened the scoring after 18 minutes, and doubled Rangers' advantage just after the half-hour mark. Akos Busaky finished off the routing with a 63rd minute strike.
Stoke moved up to third with a 2-1 victory over Cardiff, but they could fall to fourth depending on the result of Watford v Wolves later on Saturday.
Roger Johnson's own goal put Stoke ahead with 39 minutes gone, before Ricardo Fuller doubled the Potters' lead from the penalty spot. Former Chelsea striker Jimmy Floyd-Hasselbaink pulled a goal back for Cardiff, but Stoke hung on for the win.
Meanwhile, at the bottom of the table, Colchester stay bottom after a 2-2 draw at home to Sheffield United
Luton Shelton put the visitors ahead on the stroke of half-time, but Kevin Lisbie leveled immediately after the restart. Colchester took the lead on 64 minutes thanks to Chris Armstrong's own goal, but United equalized two minutes later through David Carney.
Elsewhere, Scunthorpe moved three points clear of Colchester with a much needed victory against high-flying Charlton.
Substitute Martin Paterson scored the only goal of the game after 63 minutes to earn The Iron a precious three points.
Preston remain in the relegation zone after a 1-0 defeat away at Norwich. Darel Russell netted the only goal of the game in the last minute to extend Norwich's unbeaten run to eleven games.
Sheffield Wednesday are now just one point above the drop zone after they were beaten 2-1 at home by Ipswich.
Alan Quinn opened the scoring for Ipswich with three minutes gone before Marcus Tudgay leveled ten minutes later. Alan Lee's 71st minute winner sent Ipswich into the play-off places.
Coventry claimed the divisions highest scalp, hammering Barnsley 4-0 at home.
Leon Best put The Sky Blues ahead with a 37th minute strike, before goals from Julian Gray, Jay Tabb and Best again sealed the victory.
Crystal Palace were looking to bounce back to winning ways after their long unbeaten run was ended by Leicester last Monday, and they looked like doing exactly that when James Scowcroft found the net with just 17 minutes remaining.
But their opponents, Southampton, still had time to find an equalizer, and it came in the 84th minute thanks to Stern John.
Finally in the Coca-Cola Championship, Plymouth Argyle were beaten 1-0 at home to Hull City and Blackpool ran out 2-1 winners over Leicester City.