It looked like the Chairboys were going to add to PNE's home woes as they led 2-1 going into the closing stages.
But in the 88th minute, Scott Sinclair's cross was turned into his own net by Jason McCarthy as he attempted to clear.
Emil Riis should then have won it in stoppage-time but the substitute badly fluffed his chance after breaking into the box.
Tom Barkhuizen had headed North End into a 14th minute lead, capitalising on a mistake from visiting defender Josh Knight.
They seemed to lose their way when Ben Pearson went off with what looked like a serious injury after half an hour, having little composure from then on.
Wycombe equalised three minutes into the second half through Garath McCleary, then Scott Kashket put them in front after a Joe Jacobson free-kick had come back off the post.
Some rare fortune at Deepdale this season then came their way with the own goal.
North End's starting XI had shown just the one change from the 3-2 win at AFC Bournemouth, with Paul Huntington replacing Patrick Bauer.
They could have taken the lead with just 48 seconds played, the ball having fallen to Sinclair in the box following a Ryan Ledson free-kick.
Sinclair side-stepped a defender and hit a low shot just wide of the far post when probably he should have scored.
At the other end there was an equally as clear opening when Fred Onyedinma fired over the bar from the corner of the six-yard box
For the next few minutes Wycombe had the better of the play so it was slightly against the run of play when PNE took a 14th minute lead.
A long ball forward flicked off a Wycombe head and came to Chairboys defender Josh Knight who tried to head it back to his keeper Ryan Allsopp.
Barkhuizen read it well, nipping in to jump with Allsopp and head it over him into the net.
A sweeping move down the left-wing could have seen North End double their advantage.
Ledson's ball up the channel found Sinclair who turned it behind the defence for Maguire to chase. Maguire took it on and pulled a low cross into the box to find Daniel Johnson, his shot blocked at close quarters by a defender.
North End lost Pearson at the half-hour mark, the midfielder twisting awkwardly on his left leg as he moved to take possession of a cross field pass and help it on.
He was helped off by the pitch by the physio and club doctor, not putting any weight on his leg as he went off to the tunnel.
The home side seemed to lose their way after Pearson;s departure.
Wycombe were denied an equaliser in the 35th minute when Knight's low shot in the box was cleared off the line by Ben Davies, with Ledson then blocking Jason McCarthy's follow-up.
Adebayo Akinfenwa put a header over the bar after meeting a cross from the left, then Kashket spun clear of the PNE defence to break into the box but Declan Rudd was quickly out to block.
The visitors equalised within three minutes of the re-start, former PNE winger Daryl Horgan and Kashket exchanging passes outside the box before Horgan slid McCleary away down the right-hand side of the box. McCleary drove a powerful finish across Rudd into the net.
There was a big let-off for Preston after an hour when Kashket horribly miscued a shot six yards out with the goal at his mercy, the ball slicing off his foot and well wide.
Chances were traded at both ends in quick succession, McCarthy sending a free-kick too high, then Sinclair's shot on the turn from the edge of the 'D' travelled over the bar.
Wycombe took the lead in the 75th minute, Jacobson's free-kick beating the wall and Ruud and hitting the foot of the post.
The ball bounced to Kashket who knocked the rebound into the empty net.
North End's equaliser came with two minutes from the end of the regulation 90.
Sinclair got room on the right to send over a cross low into the six-yard box where McCarthy turned it into his own net.
Riss should have won it for PNE in stoppage-time when he broke clear down the right-hand side of the box.
He sliced his shot wide of the near post when he should have at least tested the keeper or found team-mate Jayden Stockley who was offering support to the left of him.
PNE: Rudd, Browne, Huntington, Davies, Rafferty (Stockley 74), Pearson (Harrop 32), Ledson, Barkhuizen, Johnson (Potts 74), Sinclair, Maguire (Riis 61). Subs (not used): Bayliss, Storey, Holland-Wilkinson, O'Reilly, Ripley.
Wycombe: Allsop, Grimmer, Stewart (Wheeler 66), Knight, Jacobsen, McCarthy, McCleary, Horgan (Freeman 78), Onyedinma Bloomfield 78), Kashket, Akinfenwa (Samuel 84). Subs (not used): Pattison, Parker, Mehmeti, Burley, Stockdale.
Referee: James Linington (Isle of Wight)
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