S40 T4 Idle issue

**Slomo** · Monday 11th October 2010, 10:23

Hi Everyone

Within the last week my S40 T4 has started idling really badly. Up and down and almost cutting out. When the engine is warm it will idle arounf 1500. which is high...

Any ideas as to the cause?

My only thought is Idle control valve? But not sure.

Any help, ideas much appreciated

Slomo

**daveforber** · Monday 11th October 2010, 10:58

This may be of no help, but at least it'll only waste 30 seconds of time. I had this on a very old Mazda 626GT and it was because there was no water in it (it kept bursting water pipes), but essentially the ECU tried to increase the revs to pump water around that wasn't there.

Otherwise I'd be looking at IAC, though I thought if that died it would be starting and cutting out?

**gmain1967** · Monday 11th October 2010, 19:15

Originally Posted by Slomo

Hi Everyone

Within the last week my S40 T4 has started idling really badly. Up and down and almost cutting out. When the engine is warm it will idle arounf 1500. which is high...

Any ideas as to the cause?

My only thought is Idle control valve? But not sure.

Any help, ideas much appreciated

Slomo

Similar to what mine did. ICV was the culprit. Not a big job to remove and clean but to do it best, you want to take the stepper motor off as well (an additional two screws), and whilst the valve is off, clean the TB also. You might want to order up a new gasket for the valve (mine was rather second hand when I removed the valve, so just replaced it)

**GazT4R** · Monday 11th October 2010, 20:39

Tested the MAF yet?
They are a big culprit on the T4's for crap lumpy idle and other running issues since everything is controlled from the MAF.
Other than that try the ICV and check you have no air leaks.