Glad you found Dan'* writeup helpful!
I betcha if you had scanned for codes you probably would have found a PENDING P0121. Even though your CEL was not illuminated, the code would still be in the PCM. Each P-code has a specific rule for it. Some will trip the CEL light the first time the PCM sees an error and others will trip 3 times before the PCM will trip the light.
With today'* newer cars and complex sensors, I cannot stress enough to people to at LEAST purchase a $50 pocket scanner. It saves you trips to Autozone to have them scan etc.
1997 Pontiac Bonneville SEi-SCRAPYARD
2000 Chevrolet Blazer LT 4X4 4.3L
2002 Chevrolet *-10 LS Ext Cab 4X4 5.7 V8