I`ve noticed recently that the normally smooth idle on my `99 2.5 V6 will sometimes drop then immediately surge up to (circa) 800-900 rpm, then settle back to normal.....often, it`s only once or twice at traffic lights during a journey.
There are no codes showing and in all other respects the car drives and responds smoothly; as per usual.

Would the idle-valve be a likely suspect?......if so, may it be cleaned/serviced?  :-/

Possibly Miss Debs or maybe an air leak somewhere :-/

Debs. wrote on 27. Mar 2011 at 21:04:

I`ve noticed recently that the normally smooth idle on my `99 2.5 V6 will sometimes drop then immediately surge up to (circa) 800-900 rpm, then settle back to normal.....often, it`s only once or twice at traffic lights during a journey. There are no codes showing and in all other respects the car drives and responds smoothly; as per usual. Would the be a idle-valve be a  likely suspect?......if so, may it be cleaned/serviced?  :-/

It could be debs i cleaned mine out with i.p.a but double check with someone who is more in the know than me....It has not damaged mine any. :y

gstylebaby wrote on 27. Mar 2011 at 21:22:

Debs. wrote on 27. Mar 2011 at 21:04: I`ve noticed recently that the normally smooth idle on my `99 2.5 V6 will sometimes drop then immediately surge up to (circa) 800-900 rpm, then settle back to normal.....often, it`s only once or twice at traffic lights during a journey. There are no codes showing and in all other respects the car drives and responds smoothly; as per usual. Would the be a idle-valve be a  likely suspect?......if so, may it be cleaned/serviced?  :-/ It could be debs i cleaned mine out with i.p.a but double check with someone who is more in the know than me....It has not damaged mine any. :y

Will any other bitter do :D ;D ;D

idle valve , soak in injector cleaner or thinner let rest for some hours then clean by shaking (filled with cleaner) in every direction.. open its valve and clean around as much possible.. :y

ps: if you have egr and not blocked it (with metal) clean it with wd40 not thinner..

I would be blaming the idle control valve...  ;)

Thank you for the replies, chaps! :y

.....I will pull the valve, give it a Spring clean and report back. ;)

Debs. wrote on 27. Mar 2011 at 23:09:

Thank you for the replies, chaps! :y .....I will pull the valve, give it a Spring clean and report back. ;)

even brand new icv s needs cleaning after some time and from time to time Debs..  :y

Glad you ve posted this one Debs. Sounds like the exact same issue I have with my 2.0 GLS. Always on a cold engine and always in stop start traffic it idles above and below 1000rpm erratically and when Ive needed to apply my handbrake and got to Park (I have an auto) it will rev up to 2500 rpm with no assistance from me!! Very worrying  :o Any thoughts peolpe. Does this sound like the same beastie or something else. Thanks  :y

Un-metered air getting in somewhere.

Check all pipes for splits and also worth going around the top of the engine with some carb cleaner.Give it a gentle spray on all metal/metal joins and around air pipes to see if engine speed increases.If this does happen you have found the source of the air leak as carb cleaner is being drawn into engine.

ICV worth a good clean every so often,but it sound more of a air leak to me .

Thank you Amba will do that and check the ICV  :) Fingers crossed then  :y