Soot in tailpipe 1.9 DG 1990

[Brian1]

I have a bit of sooty deposit in the tail pipe after a long journey. I had an unfortunate incident where a road side repair company fiddled with the idle screw a few months ago when this was not the fault. I reset it with a Gunson CO meter. It is running fine but as I say there is a bit of soot inside the tail pipe but not excessive. I am wondering if I should screw in the idle screw a quarter turn or so? I realise this is a rather imprecise approach but it might be all this is required? Perhaps I should leave well alone!

[kevtherev]

As the idle screw only adjusts the idle speed... I think you should leave well alone.