Making ch/raise on flop I thaught I could make bluff even if he got nothing like AK or something like that.

Hand converted with online PokerStrategy.com hand converter:
$0.02/$0.05 No-Limit Hold'em (8 handed)
Known players:
[tg]MP1$5.07:///////;MP2$4.16:///////;MP3$5.07:///////;CO$5.37:///////;BU$4.00:///////;SB$5.00:///////;BB$5.58:///////;UTG2 (Hero)$5.06:///////;[/tg]
Preflop: Hero is UTG2 with A:s, A:c.
Hero raises to $0.15, 2 folds, MP3 raises to $0.45, 4 folds, Hero raises to $1.40, MP3 calls $0.95.
Flop: ($2.87) 3:c, 9:s, 8:s (2 players)
Hero checks, MP3 bets $1.20, Hero raises to $3.66, MP3 calls $2.46.