2009 Chevy Cobalt SS - P2178

I was hoping to get some ideas on how to fix this. I did a smoke test and intercooler was cracked. I got it welded professionally and that got fixed but the code came back.

Before fixing the leak, I was only able to get around 8 psi boost. After fixing the intercooler and clearing the light, I got about 18 psi. After the code came back, my max psi started dropping and now it's back to 8 psi.

Anyone see something like this before?

 

I got this about once a week for 4 weeks when I got the car until I checked the intake piping and tightened it.