Was it correct to fold here?

This guy is the chip leader in the tourney, and he was playing reasonable tight.

I put him on AQ.
Submitted by : diamondKid

PokerStars Game #18981216120: Tournament #94032442, $2.02+$0.20 Hold'em No Limit - Level IX (200/400) - 2008/07/21 - 02:49:39 (ET)
Table '94032442 35' 9-max Seat #8 is the button
Seat 1: Hero (18465 in chips)
Seat 2: skateguy (4030 in chips)
Seat 3: ucarreira (42359 in chips)
Seat 4: cusegop (5260 in chips)
Seat 6: BRAINCONTROL (25030 in chips)
Seat 7: flip1080 (18145 in chips)
Seat 8: cujobyte (9125 in chips)
Seat 9: Gargulabjjld (28447 in chips)
Hero : posts the ante 50
skateguy: posts the ante 50
ucarreira: posts the ante 50
cusegop: posts the ante 50
BRAINCONTROL: posts the ante 50
flip1080: posts the ante 50
cujobyte: posts the ante 50
Gargulabjjld: posts the ante 50
Gargulabjjld: posts small blind 200
Hero : posts big blind 400

Holecards
Dealt to Hero
skateguy: folds
ucarreira: calls 400
cusegop: folds
BRAINCONTROL: folds
flip1080: calls 400
cujobyte: folds
Gargulabjjld: calls 200
Hero : raises 1600 to 2000
ucarreira: calls 1600
flip1080: folds
Gargulabjjld: folds

Flop (Pot : $5,200.00)

   
Hero : bets 2000
ucarreira: calls 2000

Turn (Pot : $9,200.00)

   
Hero : bets 3600
ucarreira: raises 3600 to 7200
Hero : calls 3600

River (Pot : $23,600.00)

   
Hero : checks
ucarreira: bets 9200
vintageaudio is connected
Hero : folds
Uncalled bet (9200) returned to ucarreira
ucarreira collected 23600 from pot
ucarreira: doesn't show hand

Summary
Total pot 23600 | Rake 0
Board  
Seat 1: Hero (big blind) folded on the River
Seat 2: skateguy folded before Flop (didn't bet)
Seat 3: ucarreira collected (23600)
Seat 4: cusegop folded before Flop (didn't bet)
Seat 6: BRAINCONTROL folded before Flop (didn't bet)
Seat 7: flip1080 folded before Flop
Seat 8: cujobyte (button) folded before Flop (didn't bet)
Seat 9: Gargulabjjld (small blind) folded before Flop

i bet 4k on flop and then i push turn

he limp called, i dont think he had AQ

set of 4s or 8s maybe

44 is way less likely than aq
but he can have lots of hands, some that beat you some that don't, either way its the kind of flop you go allin with ak on.

well as soon as he min raises i was nervous that he had me beat, so i quickly called to see the river.

and i've seen him limp many times with AQ, AJ, etc. he very rarely raised hands.