is it set to 26 lbs or are you really just set at 20 and havening boost spikes to 26 .?that might be it . if not look for a leak.

its supposed to be set to 26 from what i can tell by the boost controller but its a knock off that was giving to me intill mine comes in so im not 100% sure it might be set to 20 and spiking but right around 4g's it wants to drop like crazy and then once your up to like 4,700 its fine i check for leaks and even ordered a boost leak tester of slowboyracing.com and so far i havent found anyleaks... someone told me it could be because of vacum ture false ???...