rough idling and lost of power

What is your question?

Truck experienced a lost of power during normal operation and then stalled. Attempts to restart was successful but the idle was running rough and there was not enough power to drive off. Fuel was checked - negative results, changed the fuel filter. Checks of the right bank valve cover connector (shaking connector), showed an improvement at times, but returned to a rough idle and lack of power. What do you think?