Hi people what can cause the revs on a saff cossie 4x4 to go, up and down when the car is first started up.The idle/revs seem to be hunting/going up and down when the car is first started up.Once its warm its ok.

 

idle control valve matey that would be your first port off call but plugs etc can have an effect wot spec you running??? bit more info would be handy

 

idle valve matey

 

Mine does exactly the same, but is a 2wd, guess it's the idle control valve/plugs as with the 4x4's though......right???

Are the ISCV's available anywhere?

 

It will also do this if running lean, so I would check the CO first when hot.
tabetha

 

As tabetha has said, usual cause is running lean. A YB engine needs to maintain at least 3%CO when cold to prevent hunting, (I actually map my engines to start at 7%CO for cold start ramping down as the engine warms up.

Check your base idle when warm is at least 900rpm with idle valve disconnected, and check the idle CO for both cold start and warm running. Perhaps you ECT sensor is faulty!

 

Its running on a stage 2 chip and on greens. I know my fuel mixture is rich and i was just thinking it could be this. Why would spark plugs cause it to idle poo. Ive got ngk irdium plugs. So how could it be the iscv surely thats doing its job isnt it. Ive still got the same problem which i would like 2 cure and the fault is that when im driving along when the engine is cold and it feels like the choke is on cause i can take my foot off the throttle and the car will still keep going. If i dip the clutch the revs rise then drop for a bit then it idles.i love my cossie but i wish i cud fix this myself without getting it looked at. Thanks for your help and keep replying please.

 

mine dus exactly the same, on stage 2 on greens, it pisses me off too
i just drive it and get i warm straiy awaw then its ok lol
but i agree it cant be iscv cus it reving on its own.
id also like to fix this

 

I think its got something to do with the weather been cold cause during the summer it was ok. I just wanna sort this fault where my car will go on its own without any throttle. My mate said it might be a faulty throttle switch. What would happen if the throttle switch was faulting.

 

I was thinkin about putting my co back to where it should be and see if that is what is causing the reving fault.

 

The fault on my car must be cause of the cold weather. I drove to work this morning and it wasnt that cold( the yellow snow flake in car was not on)and it drove spot on. It didnt drive on its own n it didnt chug like it does sometimes too. It reved up n down a little bit this morning n that was it.