MAF idle value

[FNK]

Two week ago,
I've read peak value of 157 g/s at 6240 rpm, with a load factor of 82%, which get me to about 200hp.
The idle value at 640 rpm was 3.33±0.03 g/s. (This is spot on, VE of 12% or lower is good.)
The engine felt really good.

This weekend,
The engine feel sluggish, so I did a couple of runs until I emptied the gas tank (it was the same gas tank than 2 week ago, the car was parked since then), new gas wasn't better.
The peak value recorded is now 150.3 g/s also at 6240 rpm, with a load factor of 78.2%, which is about 185hp.
The idle value at 640 rpm is 3.6±0.1 g/s. (A little higher than normal, +1%)

This confirm my suspicion.

The ECU logged no codes.

Lambda values at idle and during cruise are most of the time at -X%, even before (which indicate the fuel trim en enriched, because there is too much air, stoichiometric ratio of 14.7 must be met).
Lambda values at WOT are 0.

Timing at idle, before and now, bounce between 13º and 15º BTDC. (Is this supposed to be around 8º or 9º ?)
Timing at 6200~6400 rpm is at 30º. The timing increase in a linear pattern.

I'm not saying it's the MAF going bad just yet, I need to look at the sensor connector for oxidation. (The MAF sensor was cleaned about a month ago with MAF cleaner spray)
I suspect is that corrosion will increase the resistance of the signal. Right?
V= R*I **> Volts = Ohms * Amps

So oxidation would offset the actual value read by the MAF, this in turn is detected by the O2 sensor as LEAN burn increasing the fuel trim. Since the actual load on the engine is not as high as requested/evaluated, timing is advanced to completely burn the fuel.
If this is right, this would also explain this week very poor fuel consumption and higher engine temperature.

Sorry about this long and technical post, but I need to compare to others what are the "Normal" values to aim for, if I'm off chart, or what module/sensor is broken.

[FNK]

I made a double post, posted in the A4 section to get more view and feedback;
http://www.audizine.com/forum/showth...ag-com-results

[Crispy222]

Primary O2 going out possibly. 1.8t or v6? Stock tune/ECU? More info is needed on your setup.