Starting off. 89 with a 4.9l i6 manual tranny. The motor is running rough at idle feels like a intermittent miss, it kind of stumbles. No problem when I throttle it or when driving down the road that I can feel. I replaced the rotor, cap, plugs and wires. I thought it might be a fuel problem but I sprayed a little carb cleaning into the intake and it didn't help the extra combustible fuel seemed to make it worse. Anybody with thoughts on my next step, EGR? Fuel filter? any ideas would be great. Oh and it isn't throwing any codes.