A4 bad starting, MAF sensor?

Hi, you may (perhaps) remember I posted a few months back having failed the NCT on emissions ('02 A4 B6, ALZ engine code I think). Plugs badly fouled, then bad starting and very bad running. It somehow righted itself after a plug change and passed the NCT comfortably.

The bad starting has been back again, just when stone cold, it will fire, cough, splutter and then die. It does this on about 4 to 6 tries before it starts, then runs fine, and will start fine after a few minutes warmup. See video below (did not capture the sound too well unfortunately but shows revs). There is no codes or light.

In addition to posting here I also posted on a VAG forum and they suggested the coolant temp sensor, which I tried as it was just 12 quid. No change. They also suggested the MAF sensor and crankshaft position sensor.

I'm looking at the MAF now, it's a 4 pin type, and I got the following resistance readings (unplugged & pin numbers as written on the plug/harness) :

• 1,2 - 3.7 K ohm
• 1,3 - open circuit
• 1,4 - 6.3 K ohm
• 2,3 - open circuit
• 2,4 - 2.6 K ohm
• 3,4 - open circuit

So, it would appear that pin 3 is not connected to anything. There are 4 wires going into the plug. If the MAF just has simple resistance wires, then I found a problem, however, if there is electronics in it, these could be valid values in an inactive state. I understand there are 3 types of MAF, simple resistance, slow frequency out and high frequency out. The latter two must have electronics in them?

To experiment, I unplugged the connection the last few days, and the car is starting on the button now! It did throw a P0102 and PP0113 though. So, with the MAF connected, no errors and bad starting, disconnected, errors and good starting and running!

Any thoughts, as the MAF is at least 130 quid.