After the good fortune to ride the Sport today (always a joy, but especially in mid-February here!), I was elated to find all of the popping, hiccups, and hesitations gone. The idle was stable without stutters or pops, no lurching or "misfires" moving away from a stop or rolling on out of corners. Gone, also, was the popping and crackling on deceleration.
I had a great "long way to work" through the hills and hollers (45 miles).
This outcome is especially satisfying as the only change I made was setting the TPS (Fully closed throttle plate, etc.) from 172 mv to 157 mv. Idle was still a little low for my tastes, so I checked the Throttle Body Balance (and because I promised Meinolf I would! )
I had opened and gently warmed the mercury chamber of my MotionPro "Balance Sticks" to above the dew point to (hopefully) evacuate moisture. The mercury columns rode up solid and clear of gaps. Balance was perfect at "some rpm" (2000-3000), but way off at idle. I brought he RH air bypass screw out 1 & 1/2 turns and the LH is about half that. The mercury settled out evenly and the idle rose and stabilized.
I did not have to move the idle stop screw.
(Disclaimer: I acknowledge that Meinolf has an expertly crafted map and method to defeat the air bypass entirely.)
So, #1) I am impressed the TPS really is that sensitive. It must have been right on the break point where I could not stabilize the tune. I remember fussing and fussing with the Throttle Body Balance as it would jump back and forth suddenly trying to set the "white knob".
No way I would skip the TPS setting in the Tune-up again (I skipped it twice/ 10,000 miles and it "told on me!" )
And #2) Why do my air bypass screws have to be so different from one another now?
Over 100,000 miles/ 178.000 km and the throttle body shafts and seals are leaking air in that badly?
Something with my valves/guides/ heads?