Rough idle and poor slow speed running can often be caused by a faulty idle air supply circuit.
With the throttle in the released/closed position, the throttle butterflies are fully closed and air supply to the engine is controlled by the idle actuator, which is sited at the base of the air box. Air is drawn from the air box, past the idle actuator valve, and into the throttle bodies just below the butterflies. If you turn the ignition on and, after the self test, turn it off again, you will....