Ok the 535's been using more juice lately than it was and there seems to be a lot more white 'smoke' (for want of a better word) coming from the tailpipe than normal... Its not thicker than normal and smells normal (i think?). The smoke and fuel usage may be totally unrelated I don't know. The smoke seems to have increased since the cold weather set in (its really cold here now) so is it just that I can see it more due to the weather (like breathing out when its really cold)? I hope this isn't a stupid question but the amount of fumes coming out of the tailpipe seems to have changed a lot (although its been MOT'd recently with VERY good emissions). I had a search and someone mentioned in a thread that white smoke could suggest the car is running lean? If this is the case how do you go about correcting it?

The car's not loosing coolant (replaced it a month or two back with all hoses), and there's no coolant in the oil... I've checked for fuel leaks and none present (fuel filter changed 3k ago) and no other reasons to suspect a problem generally.

I'm hoping its nothing but it's enough to have caught my attention so i thought it best to check... Any ideas?