My car has the surges
 

OK, here's the story,

Factory rebuilt, normal ported engine with about 625 on it, and turbos with about 9,000 on them. Started up fine (normal 2.5-3k spike, then to idle,) ran fine, normal spooling response (10-8-10,) until I got off the freeway. Then the car started having power surges. It would bounce between 1.5-3k while at a stop. Pulling about -20 on the vacuum at the same time. What blew off/got stuck/broke?