Ford focus - engine code po170

[munimpatel]

Hi I have a ford focus 1.6 auto 2000 reg. The engine management light has come on and shows p0171 code - fuel too lean.

The scanning tool shows the following:
Calc load: 20%
Cooltent temp: 106 degree
stft b1: 32%
ltft b1: 3%
Engine speed: 800 rpm
spark adv: 12.0btdc
IAT: 29 degree
MAF: 1.5 g/s
TPS: 18%
02sl: 1112
02s 11: 0.2 - 0.7v
shrtft 11: 32%
02s 12: 0.67v
shrtft 12: 99%

freeze frame:
stft b1: 0%
ltft b1: 25%
stft b2: 0%
code triggered: p0171

These readings are based on car being idle after being driven for 20 mins.

In addition when I rev the engine to 1500 rpm and hold for 30 seconds : the LTFT is below 7% but the STFT comes down to about 15% from 32%

When I rev engine to 2500 rpm and hold for 30 seconds: Both STFT and LTFT are below 5%.

So far I have done the following:
changed: engine oil, oil filter, cabin filter, air filter, spark plugs, coil pack, coil leads.

I am thinking it might be a vacuum leak? any ideas?

[munimpatel]

How do I test the MAF sensor? too make sure it is good. I have a scanning tool. what reading should I be getting at idle and at 2500rpm