Cylinder Misfire Codes

[jmops]

Has Ford ever gotten around to posting the P30x codes to indicate when cylinder(s) misfire? Those codes make it so much easier to find out which ones are acting up without resorting to a scan tool or Forscan, since just a plain code reader can usually give you the info you need to track down a problem. I just acquired a laptop and a cable so I can use Forescan because my code reader puts out so many junk codes when I have a problem. Background: I replaced the cooling/thermostat box and needs to pull the intakes, etc to get at everything. I needed to redo the intakes several times in order to make everything (wiring routing, vacuum lines, etc) fit back. When restarted after some months with the PCM memory reset, it ran very smooth (indicating to me that plugs, wires, and fuel pressure were OK) until I went for a test drive and the PCM went into closed loop and came up running rough with a variety of codes that could be vacuum leaks, O2 sensor(s) etc. I've already gone back and verified fuel pressure, changed plugs, one new O2, etc. So now I am learning Forescan to sort it out. When my daughter's old Saturn came up with a misfire it was simple - switch plug, wire, injector - problem isolated, done, easy peasy.

 

[rasouth]

To my understanding about the P30x codes, the "x" indicates which cylinder is misfiring. If the PCM can't determine if there is a cylinder misfire it may not be the plugs, wires, or coil pack. It might be a vacuum leak. Start with the simplest tests like looking for broken vacuum hoses, leaking intake and go from there. When I had a misfire it ran rough, bucked and hesitated. I went through the same as you, looking and scanning, replacing wires and plugs. It turned out one of my plug wires was shorting out somewhere on the valve cover.

 

[jmops]

To my understanding about the P30x codes, the "x" indicates which cylinder is misfiring. If the PCM can't determine if there is a cylinder misfire it may not be the plugs, wires, or coil pack. It might be a vacuum leak. Start with the simplest tests like looking for broken vacuum hoses, leaking intake and go from there. When I had a misfire it ran rough, bucked and hesitated. I went through the same as you, looking and scanning, replacing wires and plugs. It turned out one of my plug wires was shorting out somewhere on the valve cover.

Of course. I wasn't looking for help, just an old man wishing Ford had their act together like some other mfrs. If all else fails I'll force it to stay open loop since I don't need to pass emissions.