Idle speed varies

[Cody82]

Yesterday when doing stop start driving for neally 1 hour the idel dropped really low and when I chucked the air cond on it stalled once. When driving properly again the idle speed was slightly higher then normal. It was really dusty but I am lost for ideas what happened as it seems fine now. Any help would be great!

 

[AttaBoy]

Check your air filter if you driven in dusty conditions.

 

[accentstencil]

May be a problem with the IAC valve.

 

[Cody82]

whats the IAC valve?

 

[accentstencil]

Idle Air Control. It sets the idle speed.

 

[Cody82]

Its due for its 140,000 service soon so i'll get them to test it (if at all possible) that probably would make sense tho

 

[Bubbaj247]

Also Check the fine filter which is where the air intake sensor is. I found my commodore to be doing the same thing, once i cleaned the little rocks, and dirt that was in it, it come good again.

 

[Wong]

please check you fuel pump should be 4volts anyhow under 4volt youhave to change new fuel pump. if you car form 2003 up..
the price fuel pump cost $350
modle 1997 to 2002 cost $150

 

[minux]

hrm, mine does this too, ever since i had a neew thing put in called a cam its weird.

 

[Slick6]

mine has started to do this latley.. usually as soon as I hit a shopping centre carpark, it just idles at about 250 and is a pain the but to drive at low speed. Usually a restart puts it back in line.

My old VT did something similar and got progressively worse. It turned out to be the IAC valve. Sometimes a throttle body clean may 'ungunk' it - (thats a technical name ) if that doesn't work from memory the part was about $50