84 GN Boost Low

[84BuickGNYorkPA]

Hey guys, can anyone help me? I have a 84 GN with a rebuilt turbo/adj.wastegate from turbo city (10-89). The turbo is fine, with the wastegate wired shut I get plenty of boost(I get right out of it). But with the wastegate shortened all the way, so I'm just able to slip the rod over the shaft, I can only get about 12/lbs eventually it will creep up to 16lbs.
Any suggestions, I'm thinking that the wastegate accuator(the part that the rod is part of) is just worn out... .
A little history of the car's tune-up so far, all new vacuum lines, PCV valve, new welbro pump/hotwire kit/ adj. regulator, fuel pressure gage, fuel filter, plugs, driver's side exhaust manifold crack tig weld repaired, TPS set at .42 idle 4.85 WOT(had to cut the bottom moons away to get it), new plug wires will be on it Wed after they come in.
Long ago parts(10-89), I bought the car new 2-84, Kenne-Bell chip, oil pressure boost plate, air filter,cam,lifters,springs, timing gears/chain, boost,temp,oil pressure gages, port and polished heads(myself/machinist) tranny cooler, gutted converter, hooker exhaust from cat back.
Thanks in advance...

 

[84BuickGNYorkPA]

Update

Turbo, intake comming off, 12 lbs. boost with wastegate wired shut. Turbo is off, intake by the weekend(if I find the time), used turbo/wastegate is on the way. That PCV rubber garment is a mother to install, heated it up in hot/boiling water to soften it up and with a major struggle got it in. Just when I thought I was getting somewhere.. . I pushed the pcv in ......it all fell down inside the intake... So the intake has to come off and the new rubber groment will get installed off the engine and I won't touch it again for 21 years!(the rubber groument)