Random engine misfire code?

Sounds like you got it well figured out.

Have you checked for spark on that cylinder?

If you replaced the plug, the wire is good, the coil is good, and you are getting a hot spark at the correct time, there is one of two problems. First could be low compression in that cylender, which is hard to believe because of the low mileage. Or, you could have a plugged or damaged injector. Have you checked to see if the injector is getting a pulse?

Here's a good one for ya guys. So I can't get this truck to set a code, at all. It has a misfire due to what looks like a vacuum leak, but (here's the weird part) we unplugged the MAF, unplugged an injector, plus the constant miss and this thing won't set any codes. Yes I have communication, live data stream. MIL comes on at KOEO. I haven't checked the ECM powers and grounds yet, but I wanted to see if anyone has seen this before. I'm not a ford guy. But I need to find out what smoked this ECM before I call it. Possibly a shorted sensor. I haven't check the 5v ref yet either. Thanks guys

Hey Al,

What burns up ECM's are shorted fuel injector or ignition coils. I would test each before plugging in a rebuilt/new ECM. Check power and grounds as well. Also unplug the 02 sensors I have seen the heater short to ground. Let us know.

Hey Ken. I actually don't think it's a bad ECM. It seems from a little research that fords have a lot of criteria that needs to be met for a mil. I've found misfire data for the #3 cylinder. But no hard faults. There's a pid #53 that counts misfires. But it's hard to find. So Im assuming the #3 isn't a dead miss yet. But I can feel it in the truck. But I will check all those you've listed for shorts to ground first.

It could be the injector shorting let me know.