City attacked from the start and had a great chance after two minutes when a James Scowcroft cross from the right fell to Jordan Stewart whose low shot drifted just wide.
Moments later Jonathan Gould came to Preston's rescue when he beat out Brian Deane's close-range header.
But after riding City's early storm Preston began to edge forward with Paul McKenna firing over from 20 yards before stunning City with a 20th minute goal.
Billy McKinlay fouled McKenna to concede a free kick in a dangerous position 25 yards in front of goal.
Up stepped Eddie Lewis to curl a superb shot over the wall and into the top left-hand corner of Ian Walker's goal.
Preston should have doubled their lead on the half-hour mark when a free kick by Chris Lucketti fell to Richard Cresswell who fired over from ten yards with only the keeper to beat.
Then after Scowcroft had headed a good chance from close range over the bar, City equalised three minutes before the break with Deane notching his 11th of the season.
Paul Dickov twisted on the edge of the area to lose his marker then crossed for Deane to turn the ball in from five yards out.
City then created two great chances before half time. First substitute keeper David Lucas brilliantly kept out Dickov's diving header before Stewart chipped the keeper with the ball bouncing to safety off the post.
Leicester began the second half in similar fashion and were rewarded in the 55th minute with Deane again the scorer.
Andy Impey angled a free kick from the right into the penalty area where Deane rose above the Preston defence to score with a looping header from 15 yards.
There was no way back for Preston and Deane missed out on a hat-trick, first heading wide from eight yards with only the keeper to beat and then squandering a similar chance in the dying moments.