After LAUNCH CONTROL = the gear shifts run through just fine = but at most, I'm only getting about 10psi of BOOST at full throttle = WHY???

2008 LNF I4 2.0L TURBO...

 

Scan it for codes. There should be 1 or more related to low boost.
Post the code #’s here. Just the #’s. Not the description of the codes.

 

I have scanned my SS = NO CODES, & the CHECK ENGINE LIGHT is not on...

 

A member had a similar problem

https://www.chevyhhr.net/forums/prob...roblems-62281/

 

You're only going to get about 14 psi from a stock SS. Maybe 15, depending on elevation. Then when you factor in that the cars with automatic transmissions have the power output limited in all gears except 3rd. Check this post https://www.chevyhhr.net/forums/hhr-...18/#post755762