Ok, so I finally pulled out my gauge cluster to see what was up with the check engine light because it had never come on. Ever. Sure enough, the bulb was missing! The guy I bought the car from was really sneaky. Anyway, so I got a replacement bulb, jumped the wires and checked for the codes. As long as I did it right, I believe I got codes:

1 - Defective or Unplugged 02 Sensor

10 - Defective or Unplugged IAT (Intake Air Temp) Sensor

41 - Primary 02 Sensor heater circuit malfunction

So where should I go from here? I mean, I already knew the IAT sensor was messed up because the black piece that it hooks into on top of the manifold is broken, so it never clicked all the way into place. But what does the sensor not being hooked up actually mean as far as how the car runs? Is this something that urgently needs to be replaced? And what about the O2 sensor and the related heater circuit malfunction? What should I do? Thanks in advance for any help with this stuff.