stumbling idle

morning to all!
i have an 00 silhouette i bought other day that sat for over a year that has an erratic idle and stumbling the longer i drove the worse it got and one day is hard to start and the next not...i checked fuel pressure was @45 lbs.. had a code for system lean nothing else. not even a misfire code, i also unplugged maf sensor and iac individually and no change. here are some readings from scanner datastream running

MAF (0.71)
MAP (13.0)
IAT (70)
IGN ADV (17.0)
ST FTRM1 (0.0)
LT FTRM1 (-21.9)
ST FTRM1 (0.8)
O2S11 (FLUCTUATING) COULDNT GET PIC TO SHOW ONE NUMBER
O2S12 (.375)
if anyone can help me figure this out i would appreciate it..i also can email pics of scanner screen i also can email pic of scanner screen

morning to all!
i have an 00 silhouette i bought other day that sat for over a year that has an erratic idle and stumbling the longer i drove the worse it got and one day is hard to start and the next not...i checked fuel pressure was @45 lbs.. had a code for system lean nothing else. not even a misfire code, i also unplugged maf sensor and iac individually and no change. here are some readings from scanner datastream running

MAF (0.71)
MAP (13.0)
IAT (70)
IGN ADV (17.0)
ST FTRM1 (0.0)
LT FTRM1 (-21.9)
ST FTRM1 (0.8)
O2S11 (FLUCTUATING) COULDNT GET PIC TO SHOW ONE NUMBER
O2S12 (.375)
if anyone can help me figure this out i would appreciate it..i also can email pics of scanner screen i also can email pic of scanner screen
Is the gas in the tank a year old?