2000 Chevy Tahoe Running rough

Checked fuel pressure and volumne, all checked out. Pulled plugs: left bank, all plugs burning rich. Right bank, all plugs normal wear.

Replacing cap and rotor and plugs with AC Delco. Replacing wires with BWD Select

BMRFIXIT, I meant to thank you for the replies, so thanks.

The only code is "random cyl. misfire".I've been told fuel, coil/ignition control mod., and Mass air flow sensor will not show a specific code. Others have said that is usually a fuel problem and it could still be, but why only is the problem showing on the left bank. I'll start with the tune-up because I want to isolate what the problem is, so then I'll look at sensors and control modules, then if all else fails a new injector spider kit.
Anyone that has any ideas, please chime in. I hate throwing parts at a problem, but I'm stuck. Thanks, D.

BTW, what type of test light for the Ignition system

Just thought of a possible fix: I found a small exhaust leak at the collector flange (I have shorty headers)so I have ordered collector gaskets. After reading this post, the second or third commit about O2sensors:
https://www.2carpros.com/forum/2002-chevy-tahoe-2002-tahoe-egr-valve-vt442666.html?highlight=cylinders+misfire+runs+rough

I'm wondering if I actually have a lean/detonation problem on the right bank(due to leak before the O2 sensor) and not really a rich condition on the left bank. Maybe not a misfire but really a detonation problem. Also noticed that during acceleration, there is no misfire, only at steady speeds and at deceleration. So would that mean during acceleration, it goes to a rich condition therefor no miss/detonation, and miss/detonation returns at steady speeds and deceleration because it leans out again.
Anyway, I will defiantly repair the exhaust leak, do the tune-up and go from there. Thanks, D.