Dead Cylinder


Hi All,

My car randomly developed what feels like a dead cylinder, it idles rough, its low on power and it generally sounds like one just isn't firing. Wondering if there is anything else I should check to help pinpoint the cause. Here is what I've done so far:

1. Connected noid light to each side of the injector harness, verified each injector is getting a cylinder
2. Used spark plug tester to verify coil is outputting spark at each cylinder - also replaced plugs
3. swapped out for a known good coil/CCCI combo - no change
4. Swapped out chip for a known good one - no change
5. Swapped out computer for a known good one - no change
6. Did a compression test - all cylinders had good compression <140
7. Checked AFR readings - at idle the AFR seems to slowly climb to and lean out to 18+ and fluctuates in this range...not sure what this means, but it should be around 14-15 as that's what I observed prior to this situation occurring.

Anythign else I should be checking to help pinpoint?
I’ve experienced this same thing and was told by those way more experienced to change the plugs. That did the trick. And the plugs didn’t look terrible. But one was