how important is MAF sensor?
 

I just used a sensor checker from my auto class and found my mass airflow sensor is only putting out around .20-.30volts and its supposed to put out between .70 and 1volt. How important is this sensor to performance. I could get another for around $100 but and a little strapped for cash right now. What would this sensor do to performance and gas mileage. BTW its a 94 ranger 2.3l.

This is an extremely important sensor. It tells the trucks computer how dense the air coming into the intake is by sampling a small amount of air coming into the intake. It has to do with the Air/Fuel mixture, but if your truck is running fine then I would just wait awhile and see.

The MAF has an electrically heated wire that is cooled by the air coming in. The more air, the cooler it gets. Many times you can take it out, and clean the wire (small small small) with a q-tip and some rubbing alcohol. It is very delicate, so be careful if you try this... the more it costs to replace, the likelier it is that you break it...
If you disconnect the MAF, the ECM will use 'default' or 'creep home' settings. If it is getting good mileage, and running smooth, I'd check my measurements again. Test it using the procedure that FoMoCo recommends...
tom