Got an annoying problem on my second turbo. First turbo boosts fine - solid 10psi , transition drops to 6psi then the second turbo holds 5-6 psi with a 'fluttering' sound coming from somewhere - possibly the dump valve.
I dont understand if the first turbo makes good boost why the second drops off ? Is it the actuator that sits on the collector i should be looking at ?

Thanks

 

no one had this problem then ?!