I have a VR 93 FD. I just found out via my turbo boost gauge that my second turbo is not kicking in after the first one engages. I know that the pattern should be close to 10-8-10 but it's like 10-8-4. everything is stock except dp, aluminum ast. I'm checking the vacuum lines but are there any other possibilities? I appreciate all the help. Thanks. Em

 

The biggest problem is the vacuum lines so I bet you will find a problem in there. It could be a solenoid or maybe the wastegate actuator.