Fold this turn?

[DeuceHigh80]

I would call this down. If he's holding a king you lose 2 more big bets. If he's holding a weaker ace or some other bizarre holding you win 8. He only has to be holding an ace a little more than one time in 4 for this to be +EV.

(this could be a mistake but I discount him holding a 4 so I don't worry about the board pairing a second time -- he got aggressive on the turn when only one 4 was showing)

I maybe giving the random bad player too much credit, but absent a strong read I think he's raising a weaker ace maybe even a third to half the time here -- the odds of him having either a K or A are the same, and A would seem to be slighly more likely for a cold call pre-flop.