Villain is loose/passive who calls with weak pairs and draws HU. I put him on a King high straight draw, so when the raise came I bet out on 6th to not give a free card. Should 7th have been check/call?

Full Tilt Poker $2/$4 Limit Stud $0.40 Ante - 7 players
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3rd Street: (1.4 SB)
Hero: A T A___Hero raises
Seat 2: xx xx 6____Seat 2 folds
Seat 3: xx xx Q____Seat 3 folds
Seat 5: xx xx 5____Seat 5 folds
Seat 6: xx xx 3____Seat 6 brings in for $0.50____Seat 6 folds
Seat 7: xx xx Q____Seat 7 completes____Seat 7 calls
Seat 8: xx xx Q____Seat 8 calls____Seat 8 calls

4th Street: (7.65 SB) (3 players)
Hero: A T A K___Hero bets
Seat 7: xx xx Q J____Seat 7 calls
Seat 8: xx xx Q 6____Seat 8 folds

5th Street: (4.825 BB) (2 players)
Hero: A T A K 7___Hero bets___Hero calls
Seat 7: xx xx Q J K____Seat 7 raises

6th Street: (8.825 BB) (2 players)
Hero: A T A K 7 4___Hero bets
Seat 7: xx xx Q J K 8____Seat 7 calls

7th Street: (10.825 BB) (2 players)
Hero: A T A K 7 4 2___Hero bets
Seat 7: xx xx Q J K 8 xx____Seat 7 calls

If villain is loose/passive you probably lost 1-2 more bets than you should have. Loose/passive players don't raise without a made hand though and he didn't reraise 5th 0r 6th so he doesn't have a straight = he's not loose/passive?

I think you played this hand well on 3rd, 4th, 5th and 6th, but I think with an unimproved pair I check and call 7th, especially since he did show some strength along the way.

Why did you just call the raise on 5th if you were going to lead out 6th when you both appeared to brick?

So I should have 3-bet it?

Or open checked 6th after calling. If he is a sneaky bastard going for a free card, you will at least know he doesnt have a made hand when he checks back at you.

What I would do there is pretty player dependent. Given that you have alot of his straight cards, I may have been a bit more likely to challenge him if I thought he was the kind of player that would often go for a free card there, but for the most part throwing lots of chips at a passive player who wakes up with a scary board isnt really a great idea.