NL400: AKo, strange line?!

[XCEO]

Just a couple of rounds on this table and I am raising a lot of hands. Villain limp/calls my raises a lot and he is pretty bad but aggressive.

Party Poker No-Limit Hold'em, $ BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Hero ($500.10)
BB ($403.50)
UTG ($161.71)
MP ($401.40)
CO ($181.55)
Button ($555.13)

Preflop: Hero is SB with A[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/spade.gif[/img]. Hero posts a blind of $2.
<font color="#666666">3 folds</font>, Button calls $4, <font color="#CC3333">Hero (poster) raises to $16</font>, <font color="#666666">1 fold</font>, Button calls $14.

Flop: ($40) J[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $32</font>, Button calls $32.

Turn: ($104) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets $28.15</font>, Hero calls $28.15.

River: ($160.30) 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets $42.01</font>, Hero calls $42.01.

Final Pot: $244.32

Is this too passive?