My Focus 1.6 TDCi 0-60 is 50 seconds

[BigMonk]

Strange one, my wife has a 2004 C-MAX 1.6 TDCi with a CVT gearbox with 42k on the clock.

When the car is cold its very slow, it gets up to 30mph without too much trouble but anything above that is hard work. However if you restart the engine when its warm then normal performance is gained and 0-60 is about 12 seconds or so, and the gearbox is pretty sharp.

I dont think the engine is the issue here, as its smooth (for a diesel) and returns 60mpg, so it must be the gearbox.

Reading the manual, the gearbox has a "cold mode" but should revert to normal operation when it gets warmed, it only seems to do this when you restart the engine.

Any thoughts?

[Defcon5]

The gearbox must have a temp sensor of some description, try that?

[Parrot of Doom]

More likely to be the MAF. Unplug it, see if there's any difference.