"Hunting"

[Peterdon]

I have a 1990 300TE-24 which has just passed its MOT:bannana: . One of the things that needed attention was the emissions. Apparently a good blast and setting the engine to run leaner solved this. However I now find that once the car has warmed up it tends to "hunt" when idling which can lead to cutting out at traffic lights etc. It now idles at 5k rpm or less when it is not hunting. It runs fine when in motion.

The question is will running a little richer cure this and if so how do I do it?

 

[punjabi]

How did you "set" the engine to run leaner!?! Mixture control ratio appears upset!

 

[Dieselman]

Inlet manifold vacuum leak.

 

[Peterdon]

How did you "set" the engine to run leaner!?! Mixture control ratio appears upset!

I didn't the garage where the MOT was done did it. Unfortunately I am a long way away from there for a while. Hence my question.