1994 Burb - consistent slight miss

1994 Suburban w/5.7L began missing at highway speed. Tach bouncing a bit as it did. It then began to stumble idle as well. It's got 207k and has been flawless.

Knowing ignition problems are easy to solve, I replaced the cap, rotor, wires and plugs with Delco parts. No difference at all. However, at cold idle I hear an obvious (to me anyway) tapping from the catalytic converter and this quiets as it warms (though it never does glow).

I am looking for advice, and for tonight I will pull plug wires one by one to see if I can isolate this to a single cylinder, and I will pump some fuel for examination and replace the filter (again, as I had a clogged one a couple months ago). Following that, I'll disconnect the cat and see how it runs at idle. I have no neighbors so they won't mind. :iceslolan

Thanks in advance for the advice found here.

Resolved.

Can you post what the issue was? This may help others who have the same issue in the future.

Thanks,
2000CAYukon

I apologize for failing to follow up on the issue I encountered.

The problem was that despite my best efforts, I had two ignition wires crossed. A 'newbie' mistake I should never have made.

To discover this, I drew a map of the distributor cap and followed each wire to its destination.