appst8design

I bought an inline spark tester and tried it from the coil to spark plug for a couple of the cylinders. It lit up for cylinders 4 and 6 but didn't light up for cylinder 2 :/ it looks like I may have a bad coil on my hands. I'll install the new coil and let you know what the outcome is.

Mr.T

The huge knock caught my eye; made me think it may be something like a failure in the valve train like a broken rocker arm or valve spring.

ronjenx

Check all the cylinders. See if 5 lights the tester. 2 and 5 always fire at the same time from a shared coil. It's a wasted spark system.
The coil-sharing pairs are: 2 and 5; 4 and 1; 6 and 3.

appst8design

So I bought a new OEM coil today from Jeep (decided to skip the cheap Autozone/Napa parts) and installed it after work. Popped it in and did a spark test (out of curiosity) on cylinder 2 and it had a spark this time. Turned the Jeep on and it was immediately running better, probably better than it has in years LOL. So it looks like the coil was garbage after all. Thanks for all the help lets just hope I didn't toast the cats while it was down in the past couple days!

ronjenx

I'm glad it's running better. I was hoping you would have a chance to test #5 before you changed coils. If the coil didn't fire for #2, it should also not be firing for #5.