Starting and idling problems

[deegee99]

I posted earlier about not being able to start my 320i, today I managed to start it up, it is idling erratically and the economy guage is now working the wrong way around ie it states I have zero fuel economy when the vehicle is idling and 50 mpg when I rev it. It also seems to want to cut out, I have checked the idle air stabiliser valve and it seems to be working correctly. However I checked the power supply to the valve and that seems to be strange. In the manual I have for it it states that there should be battery voltage at the middle pin (three pin type) I have 16V, and 10V at the two outside pins, on mine I have one reading of 5V and on the other pin 12V. After revving the engine it wants to cut out but seems to just save itself although after one attempt it would not idle at all then 15 mins later it would idle (sort of). This is with the engine warm. Anymore ideas please?