Depending on how (and if) you have organized your custom content -- by date installed, by creator, by function or in some other manner, there may be less time consuming methods to guesstimate and hone in on problem files but there is, plainly speaking, no 'easy way.'
See here:
http://www.sims2wiki.info/wiki.php?title=Game_Help:Finding_Problem_Custom_ContentThe tried and true, but time consuming, 50% method as outlined there will be of the most help in ferreting out any culprit files.
Almost anyone with any amount of custom content has encountered such problem content and had to laboriously find and remove the problem file or files.