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.

 

Could really uses some help??

 

WD40 the rod on the Bypass Valve it may be rusted costs about $5. If not replace the Bypass solenoid Costs About $55. If not you may have a leak somewhere.

 

If u replace the solenoid and that does not fix the problem. Then should I replace the valve it self?

 

Clogged cat? Bad fuel filter?

 

Unbolt your bypass valve and WD40 it and if that doesn't fix it then try getting an new solenoid from CED. My LSJ was only doing 3 psi at WOT after the WD40 I'm at 16 psi

 

Cat and fuel filter are fine. I have checked into both of them