Issues with acceleration - stuck throttle or wastegate?

[Yamon234]

So for the last 2 years or so I've had some issues with my acceleration. Somedays it's perfectly fine, other days it's a total nightmare to drive down the street. 
I can have the pedal all the way down and the car just doesn't seem to want to go. It will usually maintain my speed and/or speed up very slowly. If I leave the pedal in the same exact spot eventually within 5-15 seconds the engine will roar to life and take off unpredictably. (This unpredictable nature is why my wife refuses to drive my car currently) While this is happening I can see on my boost gauge that I'm pushing 8-9psi sometimes. (I'm tuned for around 16) 
The issue started 2 years ago when the turbo started over boosting sporadically and throwing check engine codes for it. I ran a log through my access port and found it was boosting up to 2-3 PSI over what it was tuned for and throwing the codes. Eventually this stopped happening (and hasn't happened in a year and a half or so) and was replaced by the cars current problem of not always wanting to go when I put the pedal down for that 5-15 seconds. (It's almost like the feeling of driving with a blown turbo if you can relate to that but the turbos isn't blown) If I'm driving around and I ride the car pretty hard for about 10-15 minutes I can get it working right so I'm thinking something might be sticking/stuck. My initial thought was the turbo wastegate. I have a BNR Evo 3 16g that I bought new 4ish years ago. But now I'm debating with myself that it could be an issue with the throttle. 
Any ideas/help would be greatly appreciated. I finally have my own garage and can start checking off items on my repair list. 

P.S. I recently got an oil evaluation from Blackstone labs and they said my engine was in great shape

[NORULZleggy]

It's your senor on your pedal. try to unplug the gas pedal and wait, then plug it back in. I have had this same problem and bought a new pedal assembly from Subaru and I was golden. I could be wrong

[Yamon234]

Interesting, I have heard of people having that issue. (with different cars) Did you also have any overboosting issues at all? 

Thank you for your reply! I'll definitely look into that.