White/blue smoking

Hi guys,

Had this prob for a while now on me 300tdi.
When I'm doing bout 50mph and I then go down hill with out pressing the accelerator as it goes and starts slowing down I get a White/blue (fuel I presume?) from the exhaust.
Also on the same hill going up it I always always hav to change down a gear as it seriously labours and the revs totally die as I go up.

Any ideas? Could the 2 be linked?

Have I asked a stupid question guys???

Depends on HOW blue the smoke is.Coasting down a hill then kicking the throttle for the climb is an old fave for seeing a cloud of blue smoke,hence oil burning,poss piston rings problem.

If the smoke is more white then it sounds like fuel,so its seperater clean,filter change and check ALL unions for air ingress.Check injectors are in solid and cant be twisted by moderate use of spanner on the injector flats.If STILL no good,under the dreaded rear loadspace sponge is a circular hatch that you can remove and check that the pipes and unions are good on the top of the tank.

Then start thinking about the lift pump.All easy to say,not so easy to have to do all that.Sorry,someone else probably has a better answer for you.