My 330CI will start but won't hold its revs from cold, unless I press the gas pedal slightly on start up. It starts momentarily then cuts out, however if I press the gas pedal slightly whilst starting (I can then take my foot off the gas more or less straightaway) - the car fires up fine and idles perfectly all the time. This also just appears to be a cold start problem, as it will start fine from warm starts (without the gas pedal being pressed on starting). I took the car to the local garage and the diagnostics flagged up a problem with the air mass meter. My car is still covered under warranty from the garage where I recently bought it. I told them of the problem and they told me that it is because a performance air filter has been installed. Could a performance air filter interfere with the air mass meter or is it likely that the air mass meter needs to be replaced? Advice would be much appreciated. Cheers, Dean