VR V6 idle problem

[mitchoVR]

Hi all
My Vr used to idle great but it developed a miss so i gave it a full service plugs, leads, fuel and air filter but it still had the miss so I replaced the coil pack and checked the error codes which came up ok and it was still the same however I've noticed that it will idle fine then it will miss then pick back up again and so on, also when i have the a/c on it's only idling at about 500 revs but when the a/c is off it's idling at 700revs any help would appreciated.

 

[Brett_jjj]

If the 3 coil packs where the spark plug leads go to have the cylinder numbers marked on them with white numbers,then they are the original coils and most likely need replacing.(genuine holden replacements dont have the cylinder numbers marked). They can cause a miss like the one you have described when they get old.
Sometimes even when old ones test ok they can still cause an intermittent miss.I have seen it happen a couple of times.You are better off replacing all 3 at the same time.You would be suprised how much of a difference new ones make.If you can get another coil from another car that is going, and try it where each of your coils go,(the numbers dont matter,the coils are all the same)You should be able to see if one of yours is causing the miss.

 

[hako]

I'd give the throttle body and the Idle air control (IAC) a good clean as that will cause the variation in revs with A/C on/off. I'd also check all the vacuum hoses around the throttle body. Here are the how-to's.
https://forums.justcommodores.com.au/threads/vn-vr-iac-idle-air-control-how-clean.5313
https://forums.justcommodores.com.au/threads/cleaningthrottle-body-vr-v6.6573

 

[Drazil]

Auto? Raise the idle to 950 in park. That
Should make it idle around 500 - 600 in
gear with your foot on the break okay.

 

[LS1 James]

auto? Raise the idle to 950 in park. That
should make it idle around 500 - 600 in
gear with your foot on the break okay.

say what???