When the intermolecular forces in a liquid increase, does the equilibrium vapor pressure of the liquid at a given temperature increase or decrease?
Yeah your hunch is right. Higher the intermolecular forces between the liquid particles, harder it is for it to escape into the vapor phase, ie., you need more energy to convert it from liquid to the vapor 
phase, in other words, higher its boiling point. 

If it is harder for a liquid to escape into vapor, because it is held back into the liquid by the neighboring particles attraction, you have less vapor and hence low vapor pressure. 

So in nutshell, if the intermolecular forces are increased, the equilibrium vapor pressure of the liquid will decrease.