[binions]

Fold preflop.

As played, flop call is fine with a pair and backdoor flush draw and backdoor straight draw.

When he checks the turn and you pick up a gutshot, sometimes I check behind here unless I "know" the player will fold to pressure. The last thing you want is a check-raise on the turn, forcing you to fold a hand that could have busted a big hand that he was willing to go to war with.

The reason you called on the flop was because: 1) you thought your pair might be good, and 2) you wanted to freeze him and take a free card in position if you picked up a draw to go with your pair on the turn. So, give some thought to taking the free card. Be more inclined to bet in this spot if you did not pick up a draw to go with your pair of 4s.