Weak revs, then it cuts out... ICV?

[AJC77]

Hi all,

Almost 2 years of trouble free running and I now have a brain teaser of my own :-) which goes like this....

After I've driven for half an hour or so and pull up at a red light or a junction I sometimes (not always) find the revs at idle go weak before the car then cuts out. No stumbling, no misfire, if anything the engine goes very quiet and the only check whether it's died or still turning over is the rev counter. It usually restarts ok although on one occasion it restarted but was still very weak before I gave it gas, selected first and got going.

Now yesterday when I started it up after a few weeks of not being used it sprung into life perfectly as it always has, as I left it to come up to temperature before driving (which I always do) it hit a point where the revs kept step changing from fast idle as normal during warm up to flat idle at full temp back to fast back to flat. It did this for a minute or two.

Now my first thought is to try a new ICV, before I part with £70 pounds of my hard earned has anyone else had similar, or do you have a different opinion to starting with the ICV?

Thanks in advance,

Andrew.

Ps it's the 2.9 thumper

[AJC77]

Thanks all!

It has only happened after a decent run and when thoroughly warm.

I'll start with carb cleaner on the AFM and ICV, and I'll check all the vacuum hoses which I might just replace anyway as it's probably good practice with ageing rubber.

Next question, any recommendations for knowledgeable folk (near Milton Keynes) who can properly check/adjust/set up the timing on the 2.9 Cologne? The age of our cars increasingly means knowledge of how to properly set them feels few and far between.

Thanks.