Re: 156 V6 temp. and idle problem
I'd not bother cleaning the MAF at the same time, just stick with the thermostat. Its good practice when diagnosing a fault to only change one thing at a time, isolating the component you think might be causing the fault.
I reckon you should leave the MAF alone, change the thermostat and then see how she feels, if there's still a problem, hopefully there's someone on here in South Wales with a 156 2.5 V6 who will lend you a working MAF for half an hour to test, then you will know finally one way or another whether it is MAF or something else..