Bad injectors or vacuum leak?

[gen2rt]

I have a 1994, 19,000 miles, haibeck intake & port polish, headers.
Car suddenly has no bottom end, meaning bad stumble/dies at idle, when I get into it everything is fine. Since the car sits a lot my initial thought was bad primary injector(s). After searching forum, vacuum leak also looks to be a possibility. Looking for input from anyone experiencing something similar.

Thanks,
Jack