Hi
I have a year 2000 2500 express that does not fire on the rear cylinders(5,6,7,8)
Changed those plugs: were fouled. Get spark but no change in idle when wires are pulled from those cylinders. Is there something that controls the rear? did not check compression yet, needed to let cool off.
Dan

 

So you don't have a ceck eng light? Do you actually feel a loss of power when you drive it?