Originally Posted by avacado11
Originally Posted by Mad_Hatter
Did you double check the gap for s&g? What cylinder is it on?.. move the plug(s) to a different cylinder that's not experiencing a misfire and see if the misfire follows. If it does, it's the plug. If it doesn't and the misfire stays on the problem cylinder, well then it's likely the CoP. If this leads you to suspect the CoP, you could repeat the process with the CoP to see if the misfire moves to the new cylinder. (you could further repeat this with the injector on the problem cylinder also).
Now you said it was intermittent and at cold start up, so you may need to go through multiple start ups/cool downs to get some "data" in re to the misfire moving/staying.
The issue is that I don't know which cylinder it's on. My code reader won't show any data unless there's a CEL. Otherwise, i would have swapped an old plug in and ordered a replacement.
I pulled the coilpacks yesterday and lined the inside with some dielectric grease, making sure it didn't get on the contact point of the plug. As far as I could tell the rough idle was gone, BUT the engine was also still warm.
Let the engine cool down overnight and I'm currently pulling the plugs. So far so good, plugs look normal, some carbon build up near the threads but the electrodes are clean and like new
Are you using a OBD2 dongle w/app or handheld reader?
I use a dongle with the Torque App premium. When the engines running and completed all it's checks, I can go into the app and look at each cylinder misfire count. Does yours support this feature? I know not all ECU's will, so your ECU has to support this display to begin with...but if you are indeed having a bona fide misfire it (the misfire count and what cylinder) should be stored in the ECU.