You have a vacuum leak. What gaskets did you use? The ss i/c requires a Gen 5 gasket between the i/c core and lim and a Gen 3 gasket between the i/c core and s/c. Get some throttle body cleaner and start spraying while the motor is running all around the i/c core,lim and s/c. When the idle picks up u found the leak... Is it idling like crap?Hopefully you just knocked a vacumm line loose or your gonna have to tear it back apart