Hopefully i can help..
Can you explain exactly what the current smoke problem is your having?
If from the exhaust what colour is it roughly? And when does it occur mostly?
Any warning lights come up on the instrument panel since fault occurred?
What sort of mileage does the car have on it?
And whats its service / recent repair history?
black from exhaust monthly ago 121.000mileage diesel emission test Results
Hi..there thanks for getting back..
Ok..there maybe a few reasons but of course the obvious areas would need to be checked in regards to any restrictions you can see in reagrds to the intake / intercooler system pipe work especially and obvious issues you can see in regards to vaccum system - one other common could be a failed MAF but again usually those do flag up a warning light if faulty so maybe have that checked out - Another area to maybe try cleaning is the EGR valve "exhaust gas recirculation valve" - This can be a very common area to cause the above syptoms if the valve has become stuck or simply too clogged up with soot or has a flow issue,those can be removed and cleaned aswell as the oriface in which the valves fits too - and then refitted and then see how that goes,also whilst your there maybe add a deisel injector cleaner into the fuel tank "forte diesel treatment in the yellow topped bottle" is one the best ones to help clear out the likes of injectors,once you added that then take the car on good long hard drive and see if that improves the issue .-so again this would certainly be one of the areas aswell as above to be checking anyway...the usual causes for black smoke from the exhaust can be down to either.the fuel system is delivering too much fuel into the engine or there is not enough clean air (oxygen ) either due to problems in regards to aswell as above - Faulty injectors / Faulty injector pump / Restricted airflow or dirty air cleaner/Diesel Fuel Filter / Turbocharger or intercooler faulty / Problems within cylinder head, valves clogged up due to faulty EGR (exhaust gas recycling unit)..I do hope this helps