Originally Posted by Graceland

ECU stays in closed loop mode untill one or more of the following conditions is exceeded:

throttle opened more than 35%
engine speed more than 3800rpm
boost pressure more than 4psi


So basically, when cruising along at 75mph, none of them conditions are met, ecu is operating in closed loop condition, and fuel consumption is nice and low, as are emissions and extractions from your wallet