I'm finding the Prime Vector Guidance pretty much impossible to use and understand currently.
Any time I press engage autopilot it cut's the throttle to zero before then doing what it wants (Max throttle), resulting in single ignition engines dying.
Perhaps I am missing some documentation but I could not find any.
It is also impossible to let the rocket laucnh from standstill by itself since engine spool up times don't allow for autostaging to work correctly.

This isn't a help channel, you need to look on the RSS reddit forum, the RO discord or read the wiki articles: https://github.com/KSP-RO/RP-0/wiki/TroubleshootingMechJebPVG