Depends on what you want to check. If you want to check for leaks or if you want to check how much boost your turbo puts out. First check for charge pipe leaks. Then once is scratched off the list just get a cheap obdII reader that can read the boost pressure from the sensor. Your turbo can boost up to 16-17 PSI.
First pressure test at 20 PSI, should hold above 15 PSI after 1 minute.
Then measure over a few runs, I use the Torque APP but any OBDII APP.
If the turbo was malfunctioning I wouldn't be able to drive at around 76/77 mph on the highway with ac on right?
Sometimes it seems like acceleration is sluggish like it's taking off in 2nd gear or something just like it doesn't seem to be downshifting properly when I brake sometimes I have to press the brake pedal really hard like I'm not getting any engine braking. Car only has almost 10,000 miles.
Had some times when I was on Orlando Florida on vacation I had to press the brake pedal really hard to get the car to slow especially when coming from faster speeds. Taking the car into the dealership Thursday.
You would get a code for the pedal if it was the pedal. The dealer won't do anything if they don't have a check engine light. The mechanics have gotten so reliant on digital diagnostics. Next time try tapping into neutral to see if it is really the torque converter not letting off when it should.