2.0 Turbo issues with lack of power

This has been going on for quite awhile at one point the dealer put a new turbo in the car and it fine for a little while but now it's back. It was running 13 seconds+ to 60 before the turbo was replaced. The car runs great in the morning when you take off. After I drive about 40 miles and exit the freeway I really notice the car is down on power. So much in fact I grabbed my cell phone and used the timer to record a 0-60 run of 8.3. I've taken this in multiple times for this issue and on Thursday I had the service manager drive it with myself in it. He said he didn't notice anything unusual and since there was no check engine engine light there was nothing he can do. I told him he needs to drive the service loaner 2015 they gave me and get back to me as this car isn't performing correctly. So far I haven't heard anything

Any of you guys have a similar issue? I have a year lease with plenty of miles left on this car but I am ready to be done with it