V3 wrx sti high idle and throttle sticking

[DXROLLA]

So ive noticed the missus v3 wrx sti has a high idle and in between changing gears its like the throttle is sticking, doesnt do it all the time but does seem to be getting worse. Any ideas what could be causing this?

[Dacca]

 DXROLLA said:

So ive noticed the missus v3 wrx sti has a high idle and in between changing gears its like the throttle is sticking, doesnt do it all the time but does seem to be getting worse. Any ideas what could be causing this?

Could be the air idle contol valve or some ppl call it a stepper motor, its on the intake manifold. I had similar problems,pulled this off to find it was full of metal shavings.

[resurrection.inc]

Jesus metal shavings! Ouch.... Think it only 2 bolts man easy as to get off

[kamineko]

[this applies to ver1-4 style manifolds where the idle control valve is NOT on the top of the throttlebody]

use a good screwdriver. the screws are soft and usually done tight

the two screws are used to secure the stepper winding as well as setting the idle. it would pay to mark the position before removing.

anyway once you remove the stepper, you can twist the magnet head to see how free the valve is. if there is any resistance then you need to clean the carbon buildup from the valve. either pull the thing off the manifold (you may need a new gasket after) or remove the air hose going to the valve and blast it with throttlebody cleaner while the engine is running, twisting the valve by hand until it becomes free. typically you will need some throttle as the engine won\'t like the massive air leak ;p

there shouldn\'t be metal inside there from factory, unless someone has had it apart and left it on a messy bench or something

all going well, you may need to reset the idle. do this with the car up to temp

an afterthought, you said it only idles poorly when its warmed up? how\'s your coolant? there is a coolant line that runs through the bottom of the valve which drives the temperature compensation via a bimetal spring. so a remote possibility is the line is blocked

[DXROLLA]

Cheers for the help fellas, took the idle control valve off, it was a bit sticky and full of carbon build up, so cleaned it all up and re installed it, seems to be running sweet now. Cheers