As stated above, I've unplugged the MAF sensor many times in the past, when the cumulative values (LTFT + STFT, for each bank) would go past 20 (maybe 25, it's been awhile, so I forget which), and prevent the SES/CEL from happening. I didn't want to go into limp mode, especially if I was far out of town.

That's also the reason I had 3 MAF sensors with me for 3.5 years, and would swap in a fresh, clean one after reset. That worked OK, if not perfect, until my oreiginal OEM Siemens MAF went nuts and instantly set codes, & SES, and caused driveability problems once, out of town, and I had to quickly exit the highway to insatll a backup.

That was just prior to X5chemist sending me his spare Siemens MAF, which I'm testing (if ever so slowly). So far, the X is seeming to relearn, keeping the fuel trim number reasonable, but still on the lean side.

__________________
01 BMW X5 E53,3.0i-5L40E, 7/13/01
topas-blau,Leder-grau,"resto-project car"

Here:
14 Lexus ES350,3.5L-U660E
09 HHR Panel,2.2L-4T45E
04 Chevy 2500HD,6.0L-4L80E
98 GMC Sierra 1500,5.7L-4L60E

Gone:
66 Chevelle Malibu 2dr ht.,327>441c.i.-TH350>PGlide/transbrake
08 Cobalt Coupe,2.2L-4T45E
69 & 75 C10s,350c.i.-TH350
86 S10,2.8L-700R4
73 Volvo 142,2.0L-MT4
72 & 73 VW SuperBeetles,1.6l-MT4
64 VW,1.2l-MT4
67 Dodge Monaco 500 2dr ht.,383c.i.-A727
56 Chevy 210 4dr,265c.i.-PGlide