Would you fold turn here with TPTK?

[Clownfish]

I've noticed my WTS$ is down around 27% over the last 5k hands so I'm looking for hands that I shouldn't have folded.

Villain is SLAP with an aggression of only .94. What do you think, good time to fold or just becoming weak/tight in my old age?

Party Poker 0.5/1 Hold'em (8 handed) converter

Preflop: Hero is CO with K[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">1 fold</font>, UTG+1 calls, MP1 calls, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises</font>, <font color="#666666">3 folds</font>, UTG+1 calls, MP1 calls.

Flop: (7.50 SB) 5[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
UTG+1 checks, <font color="#CC3333">MP1 bets</font>, <font color="#CC3333">Hero raises</font>, UTG+1 calls, MP1 calls.

Turn: (6.75 BB) 7[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
UTG+1 checks, MP1 checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">UTG+1 raises</font>, MP1 folds, Hero folds.

Final Pot: 9.75 BB