Let me see if I can help you on this very painful P1170. It's the left front O2 sensor not the MAF though the MAF might be needed as part of the fix. Took me the better part of 4 months of random tries to finally fix. Here are my suggestions:
1) Check the left front O2 sensor connector - use some contact cleaner to ensure you have a good connection
2) Check the left catalytic converter for leaks - get a stethoscope and listen for ticking - ticking signifies a leak (by the way this was the last thing I did and after replacement immediately solved the issue)
3) Change your O2 sensors with the real / expensive Boesch sensors - don't get the cheap ones off ebay - they don't work - replace all 4
4) Rule out the MAF - speak with Will Tillery (He's a great source and a member - he'll hook you up)
5) Look for vacuum leaks - usually pretty obvious as it will be running rough if you have one - typically the line connecting the manifold to the brake booster is a good place to start - if you have some carb cleaning spray - typically you'll get an RPM increase if you have leak so spray a little near the vacuum line connections.
Good luck my friend this was a real pain in the %$#@#@ can't believe a leak downstream of the sensor caused but it truly did.
JB
