'99 Buick Century Special: Codes P0101/P0171, where's a good GM or Buick technical forum

My wife's '99 Buick Century Special 3.1L engine, 40k miles, has been running rough and throwing codes P0101 (MAF Sensor Performance) and P0171 (1/1 Fuel Trim System Lean). I know 1/1 means upstream O2 sensor
of the rear bank.
I have a www.alldata account on this car, and the troubleshooting flow chart on P0171 says to take care of any other codes before troubleshooting that one. I don't have a scan tool.
S-o-o-o - My questions are: (1) Of all the likely probabilities, based on experience, what is *the* most likely root cause? (2) What are some simple tests to eliminate certain possibilities and narrow it down so that I can avoid a shot-gun trial-and-error mode (i.e., replace O2 sensor, problem still there, so replace MAF sensor, maybe still not fixed, etc)? (3) Any good GM- or Buick-specific web-based forums to post this to?
Thanks a lot for any help.
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Bill Putney
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Bill Putney wrote:

If the MAF is wonky it could cause the other code. All depends on what the MAF is doing when out of range. Get/beg/borrow a scan tool and watch what the MAF is doing. No other real good way of checking this out. You want one that will read live data which includes most of the 100 buck and up units these days.
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Steve W.

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Steve W. wrote:

OK - thanks, Steve.
Would the type of scan tool that the auto parts stores let you borrow (like I used to read the codes) have the real-time data capability like you're talking about?
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Bill Putney wrote:

Depends on the store and what they loan out. If it's not one of the type that shows you the code number and then they look it up for you it may.
Equus 3130,3140,3150,3160 all will show live data. The last two also will show some ABS codes.
Actron 9145,9150,9180,9575,9190,9185 all will show live data
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Steve W.

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Steve W. wrote:

I am printing this out and will see what the local Advance store has.
Thanks again.
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Bill Putney
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