I have a 1.6 TD and am having idling and starting problems. Also problems when driving at very low revs. The best way to describe the idle is like a MUM-UM-UM-UM sound. A regular rhythm of normal followed by very slow (almost stalling) followed by normal.... The car is also taking a long time to start and when it finally fires there is a huge cloud of black. Another symptom is kangerooing at low revs, particularly when I try to accelerate and use some of the low rev torque. These problems are both when warm and cold.
The car was running sweetly until I recently changed the injectors (like for like - just a 100k mile change to reduce smoking) and then tweaked the max fueling screw on the pump to get a bit more power. I've since played around with the idling speed screw and the fast idle screw to see if I can fix the problem but these haven't helped.
I'd be grateful for some advice about what could be causing my trouble.