So on a short drive last night after coming down a hill and engine braking I turned into a side road and started to slowly accelerate just as the car was coming on to boost big cloud of smoke again and the check engine light has now come on. I am yet to read the fault code as need to buy a reader.

But two things, I have been thinking about the question was this happening before the oil change and that got me thinking as to what happened at the oil change. A couple of things have sprung to mind, I used liqui moly engine flush prior to oil change, coolent change and the cam belt was changed. Now I can't see the belt causing any of the issue, BUT would the engine flush ruin the turbo seal?

Also 2 weeks ago I made sure the coolant was at max, now it is around 5mm lower in the expansion bottle. Not sure if any has been used or has just settled.

So the fault code has just turned out to be P0420 Catalyst System Efficiency Below Threshold (Bank 1). Seems to have been generated by the cloud of smoke interfering with the lamba sensor. A local garage has told me it sounds highly likely it is the turbo. So think I g going to have to cross fingers that it is and order one up.

I have looked through the net and can't seem to find anyone that has had any great problems with liqui moly engine flush. Although the garage told me most engine flushes are quite harsh so that could of added to it and the only brand he would ever consider using is Forte.