Good day, just needed some help in how to fasten the V70 XC Altenator pully?

What make the car idle then up and down, up and down all the time? When the car runs for a bit and then when we stop it idle fine no problems. Ok I will replace the MAF and then see what it does.

Must I replace the whole unit that fits to the air cleaner, or just the sensor on it?

I got an Volvo V70 XC AWD, I see that the Air mass meter is unpluged when i got the car, when i plug it in is that the car idle till its hot and then it dies... when we drive with it in the car jurkes a lot, it happens til it goes to 4000rpm. But when we plug it out it pulls fine with good power. On...