Well iys normal to hear that noise for a few seconds its the fuel pump and TB priming.
As for cleaning the sensors, dont use carb cleaner on the MAF use eletricail contact cleaner search youtube on "how to clean a maf" you should see little bits of black gine sand type stuff come out, best to clean your maf over a white peice of paper so you can see the dirt coning out.
A for that other sensor on the inlet, carb cleaner will be fine, just be careful you don't snap the resistor type thingy onit as they cost £70 to replace.
