But, would you try a new (and recommended) non-OEM MAF just to test the possibility that your original OEM MAF might be inaccurate, and might be the cause of the bad air/fuel ratio in the first place?

I sure wouldn't/couldn't rent an OEM MAF just to test with, and I would never "buy" one, test with it, and then return it to the supplier (that's outright theft in my moral code).

So, after Xchemist recommended the $23 non-OEM MAF earlier, I figured it would at least tell me if my Siemens MAF (age unknown) is under-reporting the g/s airflow, and triggerering my lean codes.

• 1) At best, I get a solution, after which I'd buy a new Siemens MAF to use (as soon as I get the $$$ to buy it, and keep the $23 unit as a known-good spare),
• 2) second-place result, with no change or very similar to the lean codes and g/s readings I'm already getting, I've got evidence that my OEM sensor is still OK, and I've got a spare, and
• 3) worst case result, as the $23 MAF shorts out my DME, and the X5 burns to the ground, then I made a mistake and I lost $23 and my X5 (but proved those doubting the reasons to get a cheap sensor to be infallible).

__________________
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