shaking when ac is on

[jimmythesaint]

question,,,the wifes vz when at traffic lights shakes and shutters with the a/c on when ya turn the a/c off its ok ,,,,,
could it be the injectors,,,really confused,,,did have a sluggish problem before but thats been fixed wiyh new spark plugs,,,,
it starts coughing and shaking in drive or reverse mainly in park not so bad,,,but only when a/c is on,,,,any ideas,,cheers

[loopie]

iac valve, or some people call it a idle up control valve, basically it increases the car idle when the air con is on.

[Danoz]

The vz has an electronic throttle so it just opens up 1-2% more when the AC is on. It has no IAC valve.

You should clean the throttle body... See if that helps. They build up a bit of gunk just after the butterfly.