Testing ignition coil w/Spark Plug test light?

[hear]

I'm chasing a P0301 misfire on my 02 and had a (potentially stupid) idea on how to test the coil. I've used one of these before on my 97 to verify if I was getting spark. Obviously with the coil-on-plug setup on the newer TJ's you can't just plug one of these in. But you probably can plug SIX of them in.

Is this a terrible idea for some reason? Whether or not I'll be able to SEE the misfire is another story. Assuming an idle of 700 RPM, that means each plug fires ~24 times/second (since each plug fires twice per cycle), if the misfire is intermittent I doubt I could see it as anything more than a brief flicker.

 

[Jerry Bransford]

The same coil for #1 also fires the #6 cylinder so it's unlikely the coil itself is bad since the #6 cylinder is not misfiring. Have you checked inside the #1 plug connector inside the coil rail to make sure you can see its metal contact is still there and looks like the other?

 

[hear]

The same coil for #1 also fires the #6 cylinder so it's unlikely the coil itself is bad since the #6 cylinder is not misfiring. Have you checked inside the #1 plug connector inside the coil rail to make sure you can see its metal contact is still there and looks like the other?

I haven't, but I also happened to have a new coil laying around and swapping them out didn't change anything. I just had this little idea to verify if the new coil was god out of the box.


My next step is to swap the #1 & #2 injectors to see if the misfire follows the injector.