I have to say I really hate this.

If his 3bet means Ax you have 5 outs on the K and Q, plus 4 straight outs on the J. Folding for one more bet here is wrong even if he isnt bluffing.
If he is utility betting with a hand like KJ or K9 you are well ahead and giving up a decent sized pot.

If your going to try any line like this I would call this turn for your cheap card and raise on the river. This ultra tricky play will really hurt you in the long run, particularly at low and micro limits.