josh1506 Posted February 17, 2016 Share Posted February 17, 2016 Have an 08 MKZ that has cylinder 4 misfire. Also the ac stopped working when the misfire happened. I have read about it happening on f150's. Wire insulation was worn and shorted both out. I've tried looking to see if I could find a short or bad wire but cant. Anyone else have a similar probably? I've checked around where wires have contact with engine but cant find it. Any help is appreciated. Quote Link to comment Share on other sites More sharing options...
4N1M4L Posted February 22, 2016 Share Posted February 22, 2016 On my 2010 the compressor wouldn't kick in during a misfire to keep load off the faulted engine. When I replaced the faulty injector the ac came right back. Be careful driving on misfires. It can lead to a ruined catalytic converter if left that way. drolds1 1 Quote Link to comment Share on other sites More sharing options...
josh1506 Posted February 22, 2016 Author Share Posted February 22, 2016 I had someone check it out the wiring and found nothing wrong. But the #4 cylinder will not fire. I thought maybe it was a short or something but he couldn't find anything. I have read of the pcm going out and was hoping that wasn't the problem. Quote Link to comment Share on other sites More sharing options...
drolds1 Posted February 23, 2016 Share Posted February 23, 2016 Have you inspected the coil on that cylinder? Is it blistered, burnt or cracked? Did you try swapping coils to see if that cylinder fires with a known good COP?  You haven't mentioned if the CEL is lit. If so, what are the code(s)?  What usually happened with these is that a bad coil took out the ECM, not the other way around. There was a TSB for coil/ECM failures in certain instances.  As 4N1M4L states, don't drive the car with a misfire. You don't want to be paying for catalytic converters on top of the existing problem. Quote Link to comment Share on other sites More sharing options...
josh1506 Posted February 23, 2016 Author Share Posted February 23, 2016 Cel was on for cylinder #4 misfire. Check coil and looked fine. Replaced coil with new one and new plug and still dead. Swapped out other coils and still the same. He told me there was power to the coil but not a stable ground from the pcm. Quote Link to comment Share on other sites More sharing options...
4N1M4L Posted March 4, 2016 Share Posted March 4, 2016 Injector?? Quote Link to comment Share on other sites More sharing options...
manchildsgt77 Posted September 10, 2022 Share Posted September 10, 2022 Having the same issues. Was a cause found. From what I found out so far online is that it could be an ECU issue or it's wiring harness. I've changed all new spark plugs and the ignition coil for the cylinder that is misfiring. But this hasn't solved the problem. I am wondering is there another way to test the system which would identify this as a ECU malfunction. Quote Link to comment Share on other sites More sharing options...
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