Re: Frikking 3.7
It will not test the MAP nor IAT, but will show the live data from the sensors. The MAP should show actual barometric pressure with engine off and will show a much lower value with engine running. The IAT should show outside temperature when the engine is cold.
For the O2 sensors, you will have to look at the upstream sensors, ie the 1-1 (bank 1, sensor 1) and 2-1 (bank 2, sensor 1). The voltage should jump up and down between 0.2-0.8V and the STFT (short term fuel trim) should read a single digit value (mostly +- 5). This is on a steady running engine, not during acceleration. If the STFT becomes double digit values ( so +-10 or more), it is a sign that something is not regulating well. Can be for example due to a faulty O2 sensor, low fuel pressure, vacuum leak or other problems.