'Hunting' at idle........

[punjabi]

Got stuck in heavy traffic in London's East End last Saturday, my W124 300TE Auto moving at snail's pace for about an hour, resulting in a sudden 'hunting' mode in idle but would clear once driven! Since, it has retained that tendency despite a visual check to ensure that all is ok under the hood - plug cables, etc.
Any idea what could be causing this?

 

[markmifsud]

Hunting is nearly always die to an air leak, check all vacuum hoses / connections. Might be worth getting a tin of wd40 and spraying that around areas where you can not check for leaks, if it gets sucked into the engine you will notice the engine rev alter

 

[nick.ged]

+1 for the above. hunting is almost always an air leak

 

[nunocrzt]

+2

Generally a broken hose might be the cause.

 

[lynall]

Couple of my wifes old cars did this and every time was down to carbon on the throttle butterfly, drove okay just had uneven idle and also gearchanges not as nice as usual, carb cleaner and toothbrush all okay again.




Lynall

 

[nick.ged]

+1 for that as well, that is usually the other 10%