2000 K2500 4x4 7.4L 454. Trouble code shows misfire on #4 cylinder. I have replaced the cap, rotor, wires, plugs, and fuel filter. Still a misfire. Hesitates during acceleration, no power at speed. Seems to run (ok) when cold, gets worse as engine comes to op temp. Could it be in the distributor? ECM? Coil?