Yes, there is FTL capabilities outside of Starburst. Starburst is wholly unique to Leviathans. The main reason that the Peacekeepers and others couldn't keep up with Moya isn't because they lacked high speed travel, but because Starburst is pretty much random for the most part. Sure, Pilot and Moya could calculate a Starburst to try and get close to where they wanted to go, but to an outside observer they basically just disappear. There's nothing for them to track or plot a course around. Which is why Starburst was such an effective defensive move for Leviathans.
But yes, when the Peacekeepers were able to track Moya courtesy of a device they hid onboard, they were more than capable of catching up to her on a regular basis.