Maybe we're working the wrong end of the problem. Could it be you have a bad MAF sensor? It can be tested or you can buy one cheaply on ebay to substitute. Here is the link to Clark's Garage: http://www.clarks-garage.com/ Check the shop manual under "A."
I know that some cars have a "limp home" mode that will allow the car to start if the MAF sensor is unplugged, but I don't know if the 944 does. Maybe Ian or someone knows more about the symptoms of a failed MAF sensor. I have never had the problem (had almost every other one though!)