I don't really know how to use a multimeter that well. I'm just going to buy a new MAP sensor, because the one on the car is CLEARLY broken and I can get one from a guy down the road for probably $5. If he asks for more than that, then I'll test it before buying one. While researching though, I kept seeing that people were emphasizing that if you're replacing the MAP, to make sure to replace the MAP gasket. But where does one find a new MAP gasket?

 

The MAP sensor has a funky silicone rubber seal, just like the seal on the fuel tank pressure sensor. They are one use only, take the sensor out and the seal is junk. Available at the dealer only, as far as I know, (that's where I always get them).