I have a '91 940 16valve and have replaced the sensor in the air box last year but am now having the same problem of stalling out at idle. My mechanic said too much hot air from the manifold could be frying the mass airflow meter so it wont work correctly. He suggested that we remove the hose from the manifold to the airbox and if the car ran ok it would be either the sensor ($35) or the mass airflow meter ($250). Car runs fine now but I need to get it smogged. Is there any way to clean or rebuild the mass airflow meter or to modify the airbox or flaper valve inside so no air gets thru from the manifold (the car is only driven in California so I rarely woud need the hot air to preheat). Any suggestions would be appreciated.