Volvo: S70 not accelerating in cold weather, mass air flow sensor, mass air flow

Question
I have a 2000 turbo S70 with 150K miles. Intermittently in cold weather it won't accelerate. The first time, it had been sitting outside all day (temp 20 degrees) and when I started it up after work it wouldn't go more than 20mph- I let it warm up for 10 mins and then it was fine. The next time, I had been driving the car for ~30min at 60mph and when I merged onto the interstate it wouldn't accelerate into traffic- it wouldn't go faster than 60mph with the gas pedal pushed to the floor (temp was 0 degrees).  The next time I started the car, it was much warmer outside and it accelerated just fine. The mechanic I consulted stated he thought I might need a new MAP sensor, but couldn't get it to malfunction- so he advised against replacing it. Any thoughts?
Thanks!

Answer
Carrie,
There is not a MAP sensor, but there is a MAF sensor. That is Mass air Flow sensor. The MAF does have a high failure rate. Best advice, get the car to a shop that works on Volvo's. You are better off spending the money on a shop that knows your car. Have the fault codes read and see what they might be. There are reading that can be taken using the scan tools and that will help to determine if the MAF is at fault.