I have a 2005 Cobalt ss s/c it has 114xx miles. When i first bought the car I new it had few problems. But one I cant figure out is I cant boost over 8 to 9 psi. Then randomly ill start boosting around 13 psi but then I pull -10 on my vvaccume No mods becides cold air intake and exhaust. I replaced mass air flow and 02 sensor I pulled off throttle body and cleand it too. Could the by-pass vale cause this or would it be the by-pass valve ssiloned.

 

you need to post this in the problems and service section

search how to do the bypass mod that will tell you if its the actuator on the blower or the solenoid