It's highly unlikely to be a turbo problem. They generally either worked, seized shut so they over boosted, or just blew up (which even that was pretty rare).
If the actuator had failed, it would over boost as they're old school and use boost pressure to open the wastegate.
Given what you've said, it's far more likely to be an EGR or fuel pressure issue.
If the actuator had failed, it would over boost as they're old school and use boost pressure to open the wastegate.
Given what you've said, it's far more likely to be an EGR or fuel pressure issue.