I have purchased the same tool mentioned by you. This is the list of the sensors for my car that the ECU can read / the ELM 327 can read from the ECU. Specially i expected the Exhaust temperature sensor and the CO2 produced.
During routine inspection by MSIL i asked them to scan by their diagnostics tool and it showed the error Code for "Glow Plug" and by this device it haven't showed.
Can you please upload the list of your sensors by your device.
After Cleaning the MAF sensor it gave me reading about 8.0 to 8.2. Outside Temperature was around 28 Celsius and humidity of 72%. Car was shut off for about 2 hours. whereas your were 5.4 before cleaning and 4.6 after cleaning.