Hi Matt, I've been chatting at length with the dealer. Initially he was advised by a German ex Mercedes expert that these models [built for UK, shipped to African altitudes] had issues with timing of inlet and exhaust. A few vehicles like this very one were imported brand new way back then andhad the same problem. Through consultation with Mercedes, remapping of the ECU was done, Mercedes providing a "window" for this to be done via their diagnostic regime. So, he is inclined not to rush to replace injectors. Live testing in our country is difficult, we have to remove the injectors and send to South Africa for this to be done.
Here's something I read via MB Forum: [just about described what I am facing!]
"Today I had a new occurrence of the smoke. New injectors did not fix this. It appeared just as before, after driving at slow speed on a more or less flat road. This time in quite some tailwind. When stopping at a junction it was pouring out a lot of grey smoke which disappeared relatively quickly after gaining speed again.
Is there any parts of the EGR system or turbo that could influence this?
The engine is running great and starts easily and do not seem to burn much engine oil ore coolant, but I don't like this situation of not knowing what is happening, and fear costly repairs."
WE HAVE THEREFORE JUST JOINTLY DECIDED TO CHECK THE EGR VALVE, IT WILL COST $300-400 TO REPLACE IF NEEDED. LET'S SEE HOW THIS GOES, I WILL KEEP YOU POSTED