So, to start from the beginning My car was running a bit rough in the heat and I couldn't figure out what was causing it.(Ran almost perfect in cold weather, which I live in washington so its cold most of the time.) And I replaced all my struts, brakes, and so I needed to go in get an alignment so I took it to midas and I figured while it was there i'd just pay the 98 bucks to get them to run there bull**** test to see if they could find any codes (it does not and never has had a CEL) which it pulled a code for fuel pressure regulator which whatever replaced it wasnt that, and they said they found a vacuum leak on my supercharger with a bad O-ring somewhere. So I thought cool beans well its something. Well ever since I got it back from them I can't build boost correctly and whenever it tries it starts jolting. I don't know what they could have done. no matter what I do I don't get more than 1 psi of boost and has no power feels like i'm driving a n/a car. any help would be appreciated.
'02 Pontiac Grand Prix GTP, 188k, no mods atm most i've done to it is take care of it and have a k&n box filter.
