Your Views, please: MPG - Temperature or Air Mass Meter.

[SAFC]

I've had two occasions recently when the turbo seemed to be non-existent and a simple switch-off and re-start brought everything back to normal.
This hasn't happened for about 8 weeks now but my Indy Merc pal tells me that the Air Mass Meter (if that's the right name) might well be on the way out. The good news is that for a W203 270 CDI he can get me one for about £60.

I'll leave it to see if it worsens but what I have noticed is that the mpg has gone down.

Now, given that today my car could not reach proper operating temperature over a distance of 16 miles (it's freezing out there) I'm wondering if the drop in mpg is....

a. Air Mass Meter getting worse - but I've not had the no-turbo symptoms or
b. The CDI engine simply uses a lot more fuel in very cold conditions.

Any views, fellow Merc-Nuts?

 

[tagnut]

If your engine isn't getting up to temp then fuel consumption will be higher. What temp did it get to? You could have a faulty stat.

 

[Stratman]

It isn't necessarily 'either/or', it could be both.

The MAF and thermostat are both fairly common failures.

 

[SAFC]

In normal conditions the engine does reach normal temp i.e. 82/83 degrees.

 

[SAFC]

Further to my querey: Let's say it's Summer (ah, Summer, I remember you!) and the outside temp's about 15-20 degs C - about as hot as we get up here. My C270 CDI takes 5 miles to get to 82/83 degs - Is this normal?
By normal I mean: Is 82/83 degs about right and is 5 miles about right too?