With Wolves losing to Coventry, Reading will be angry at missing a great chance to move three points closer to the leaders.
Despite being on the back foot for most of the game, it was Preston who had the best chance to win.
Ten minutes from time Preston substitute Chris Brown found space on the left and sent a cross into the box. It found big Jon Parkin totally unmarked but from eight yards out he shot high over the bar.
Reading had the best of their chances in the first half, but Preston keeper Andy Lonergan twice made excellent saves to keep Reading from scoring.
His first came as early as the 11th minute with a good reaction stop from a shot by Reading's Mali-born midfielder Jimmy Kebe.
His second came after 23 minutes when Leroy Lita had been put in the clear by Kevin Doyle.
Lita raced forward and sent in a powerful shot only to see Lonergan spread himself and make a save with his leg.
The Preston keeper had just one shaky moment when he dropped a miscued attempt at a clearance by Youl Mawene.
Kebe got to the dropped ball but his close-range effort was blocked by a defender.
Preston relied on the muscular Parkin and lightweight Stephen Elliott up front, but Elliot was sternly lectured by referee Michael Jones after one challenge on Reading's Australian keeper Adam Federici.
Keepers were in the limelight again when Lonergan laid out Reading striker Kevin Doyle in a challenge for the ball.
Doyle lay motionless for some time before recovering sufficiently to continue.
There was an early fright for Preston in the second half when Lita's free-kick from just outside the penalty struck a defender and looped up into the air.
Doyle tried to bring it under control but it was scrambled clear before he could shoot.
Stephen Hunt then sent in a cross which Lita saw saved by Lonergan as Reading grew increasingly frustrated at their inability to make the breakthrough, despite doing most of the attacking.
Twenty minutes from time, Reading manager Steve Coppell decided to gamble on snatching a late winner.
He took off midfielder Kebe and replaced him with a third striker in Noel Hunt.
Then he took off skipper James Harper and put on Czech international Marek Matejovsky in the hope his passing skill would open up Preston's stubborn defence.
In a final attempt at a breakthrough, he replaced the tiring Kevin Doyle with compatriot Shane Long, but it was all to no avail.