Aiyegbeni Yakubu marked his debut for Sven Goran-Eriksson's Foxes with a first class strike to give the Foxes the lead.
However, the Nigerian hitman's first goal for the club was not enough to earn Leicester all three points as former Fox Iain Hume had the final say on an entertaining encounter, striking at the death to give the Championship's bottom side a morale boosting draw.
Eriksson made just one change to the side that played out a brilliant 2-2 FA Cup Third Round draw against Manchester City last Sunday. Darius Vassell - sidelined with a hamstring injury - paved the way for Yakubu to make his debut in attack.
Leicester looked the better team for large spells this afternoon and Phil Brown's men simply couldn't cope at times with the threat of Yakubu and Paul Gallagher going forward.
In the first half Lloyd Dyer saw his powerful drive fly past Andy Lonergan's post before Paul Gallagher struck a post with one of his trade mark free kicks from the edge of the penalty area.
Nigerian International Aiyegbeni Yakubu then came to life, and showed the Leicester fans what they can look forward to from the on-loan Everton man when he took on three defenders before finding space to fire an effort at goal, but Lonergan made an equally impressive save to keep the match goalless at half time.
The Foxes made their intentions clear early in the second half and Paul Gallagher should have given Eriksson's men the lead when his header connected with Kyle Naughton's centre, but he was yet again denied by the woodwork.
For all of the Foxes running, it was Preston who could have taken an unlikely lead moments later when former Fox Iain Hume gave the City defence a gentle reminder of his presence, but his 12 yard effort was well saved by Chris Weale.
Leicester did finally get their goal on the hour mark when Yakubu once again emphasised the Premiership quality he possesses to find the net via his favoured right foot.
The Foxes now had their tails up and Kyle Naughton should have put his side out of sight, but his toe poke sent the ball the wrong side of the post to give Phil Brown's side just a glimmer of hope.
Whilst the away side continued to dominate play, there was always a sense that the Foxes could be punished for their failure to convert their chances and Iain Hume was more than happy to oblige in the most agonising fashion when he struck a well taken equaliser one minute into stoppage time.
A hopeful punt up field by Andy Lonergan was flicked on by Hayes into the path of Hume, who turned with the ball before firing past Weale to send Deepdale wild.
The result sees the gap between Leicester and a play-off place grow to six points as they fall to 13th while Preston remain rooted to the foot of the table, a worrying seven points away from safety.
The way in which the Foxes let three vital points slip out of their grasp will have Eriksson fuming but he will know that on another day, his side could easily have ran riot on a shaky Preston rearguard.
Eriksson and his squad will now turn their attention to the glamorous FA Cup Third Round replay away at Premier League giants Manchester City on Tuesday night.