I have had that code before, it is definitely air flow related. Most likely it is emmissions related. I've had it both on my 328i and X5. And in both cases I unplugged the MAF and reconnected it to make sure there is a good connection. Then I have garaged my 328i because it is the worst about MAF codes because I upgraded to the Stage 3 K&N intake (more problems than it's worth sometimes). The most important thing is to let the car warm up for a couple minutes before you drive it to let the secondary air (emmissions) pump cycle. If you do end up having to replace the MAF check out the Dinan website the performance version is very close to the price of the standard MAF price at Autozone or O'Rileys. Definitely avoid a "stealer" if you can. Hope this helps.