My car has developed a high idle, it appears to be intermittant, and does it when hot and cold, also when in gear as if the throttle is stuck open slightly, (will check the butterfly at the weekend, but i did start it from cold earlier and for about a minute idle was perfect, then the revs built up to 2k on there own without me touching the throttle at all, so rules out the butterfly really?) i have checked for any post throttle body leaks as well as possible, just wondering what other things could possibly be causing this?, Lambda?, Idle valve?, TPS?, etc, etc, helpl will be greatly appreciated thanks

 

Sounds like idle control valve is sticking. It's basically a rotating barrel which can get grimed up over the years... worth cleaning with carb cleaner or brake cleaner & a cotton bud etc. You need to get a new ICV gasket though as these expand when you remove the unit from the throttle body and you'll never get it back in!

 

Aslo the MAF sensor could be giving up and sending faulty readings which can lead to a fast idle.

 

ok thanks for the replies, my car is mafless, i might give the idle valve a go.

 

You have the same setup as me. Just take the idle valve off and clean it with wd40 or similar and cotton buds. Put it back on and if still a high idle adjust the rotation of the valve with the two screws till its perfect (remember to mark the original position in case it is not the cause).

 

Any other suggestions, other than idle valve?

 

I have the same problem, any ideas guys,

Also how do you take the idle valve off on a MY98??

Damo

 

idle valve i would say also, had mine reving to about 2k ish. Red some post on here, problem was fix by cleaning and a little tweak.
Think i rember they cost a fare few quid.

 

I have the same problem with my MY97 sport,any ideas??,
Also how do you take the idle valve off on a MY97 sport??
Thanks in advance
Gazza