can't keep boost level constistant

[insanedsm2403]

Hey what's up everyone.I have a 90 tsi awd I just got.runs great and pretty much stock except 2 1/2 inch 02 housing with external dump and 3 inch from there back.I have a turbo xs boost controller hooked up to my bov for pressure source.now the problem is 1 out of 5 times it might hold boost at 10psi and the rest of the times it will fly up to about or past 20psi on my autometer boost gauge.I have put a brand new waste gate actuator on it and also left the wga arm off the flapper to test for boost creep.several runs up to 7k proved to give me not one psi of boost.next I cut all my to boost contoller and gauge hoses as short as possible and still I spike to 20psi.when it holds at 10psi its a wonderful feeling,but most time it will spike high and hit fuel cut but I usually let off once it goes to high for my likeing.boost controller is set as low as possible and I'm just about out of ideas.any help or suggestions will be greatly apprecited.thanks a lot everyone.ok I just got back from a few rides and I've been noticing that I have a better chance of holding 10 psi if I start slow and then floor it, it
will probably hold until redline.now if I mash the gas most likely it will fly past 10psi.I also noticed the higher in the gears I go the harder of a time it has staying at 10psi.

 

[killer_eclipse]

have you tried taking the boost controller off and see if you still have the spike problem....? and is your wastegate adjustable or is it stock?

 

[oldcarguy85]

i've never used that boost controller, but are you sure u don't have it plumbed backwards?