Well, I am getting ready to replace the mass airflow sensor (MAF) in my 90 240 SX. I called a friend at a Nissan dealership and he said they were like $540 and he could do it for $440 for me, but I also called Autozone and they had one for $95 plus a $90 core charge, so I will prolly do that. I would imagine that there has to be one that would work from another mazda vehicle, but I am not sure. Check your local parts stores and see what they say, better than paying full boat at a dealership.
Peace
Griff