VS idle

[Vs_ss_gmtank]

Ok I have a vs ss 5lt manual.

Now on start up the idle goes a bit over 1k revs then drops right down to around 700-800.

Thats cold idle and also hot idle..

But sometimes when its idling in the morning or at a set of lights it will sit at around 700-800 but then dip down to about 400ish for a few seconds then go back up to around 700-800 revs.

not really sure how ti go about to fix the problem, because surely seeing it idle at around 800 then just dip down to around 400ish revs for a few seconds then go back up is not normal?..

I'm pretty sure its been doing it for sooo long but never really took any notice but thought I should suss it out now!

[BlackVXGTS]

Try replacing your throttle position sensor - around $30 from Repco.

[Vs_ss_gmtank]

is it hard to change over.

[Scooter79]

Throttle Position Sensor just screws to the throttle body. But I really don't see what the problem is. Unless it's causing grief I wouldn't worry about it.

[CNsylvester]

I started mine vs v6 today and on starting it make a sound like "pewch" or soft mini backfire, then it started to idle inconsistantly at traffic lights etc, but otherwise drove as normal on freeway at 100km. I have been slightly grazing speed bumps recently, could it be something do with exhaust due to minor bottoming out? THe care is not driven hard and no dogey fuel has gone into it that I know of.

[BlackVXGTS]

is it hard to change over.

Easy to change but you need to take off the throttle body to do it properly and make sure you don't lose any of the bits.