Hello again, thank you for your reply.
As the engine management light is on then a fault has definitely been detected by the engine management. Depending on the equipment some manufacturers specific codes may not be read.
I personally would have the engine management checked using the Ford IDS system.
When a fault is detected by the engine management usually the glow plug light starts to flash and depending on the nature of the fault the MIL will illuminate. As in your case only the MIL is on then this will be an emission related fault.
Check that the Exhaust Gas Recirculation (EGR) valve isn't sticking, this valve is for emission purposes, if it sticks open then exhaust gases are sent into the engine when they shouldn't be. This has the effect of starving the engine of fresh air which causes over fueling hence the smoke. If a fault is detected by the engine management then the engine management control module will switch to limited operating which reduces engine power.
There are other concerns that can give these symptoms such as fuel pressure concerns but as I said earlier normally the glow plug light will flash.
Another common concern is the turbo system rubber hoses split, check the hoses for splits especially the hose from the intercooler to the inlet manifold, you may need a mirror for this as the hose tends to split on the underside, again a split hose gives a lack of power and smoke due to over fueling.
Start with these checks, as the MIL is on then there is certainly a fault code stored.
Let me know if I can assist further or if you have more questions regarding this and I'll reply as soon as I can.
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