MAF is usually the upper rev range - 4000 + so probably not this.
Maf output and lambda can be checked on AlfaDiag - £80 to buy so cheaper than hook up to dealer's machine.
1. Rubber induction hose - the one with the bend that goes into the throttle body - this fails underneath the ribbed bit due to the oil crud that gets sucked in from cam cover. The only way to check properly is remove it and flex it. A quick temp fix (and check) is a good wrapping of duct tape. This is less noticable at higher revs as the air leakage is negligable compared to the lungs full of air the V6 is sucking in. At low revs you're running a very lean mixture.
2. Dirty throttle body - the stepper motor flap gets dirty with oil drawn in from cam cover and upsets the idle/low speed setting. This can be cleaned when the above inlet pipe is removed - carb cleaner toothbrush and a little care. Move the flap very slowly or you can damage the stepper motor. Then do an ecu/throttle reset.
3. Plug and or coil pack. 96 k is long time to go for coil packs. The way to test is take off and replace each fuel injector plug one by one, when you get no change in the engine sound you've found the duff plug/coil pack/cylinder. To check if its a coil pack, swap with one of the other cylinders and see if it "moves" to that cylinder. If it doesn't then its the plug not the coil pack.
The plugs should
have been changed at 60k, so they could be getting a bit tired at 36k. It is not uncommon for the rear bank of plugs to NOT be changed ay 60k even by main dealers (from personal experience) as they are a complete pain to change - this applies to coil packs too!
5. V6 is very fussy about a good battery for best perfomance (so called relaible German Bosch electrics.....