VT Calais

[Super6VT]

Hey everyone.

I have a Supercharged VT calais. Problem is when i start it, it runs rough and idle drops to around 200/300rpm like its about to stall. still does it when warm but not as bad.
When under load the car kind of flutters/shudders like it has trouble getting the revs up. no power its gone weak.
when i rev it from under the bonnet it doesnt have an issue with it.
Just replaced rocker cover gaskets and leads and plugs.

Car isnt overheating

Ideas?

cheers guys

[Mirkz]

fuel lines/pump been checked?
Any codes being thrown?

[monkeys437]

Checked all the vacuum hoses? The hoses around the bypass valve and to the throttle body can perish over time

[showbags]

Had the same thing with mine wasn't over heating, but then radiator started leaking and when I replaced it the problem disappeared. No one can seem to tell me why.

[Jamiejamie]

Could be when you changed over plugs and leads. Did you have the correct gap?

[chargedvx6]

have you checked the vac hose that goes under the throttle body? It goes from the drivers side head where a solenoid is around the rear of the engine to the throttle body. Can easily slip out

[mbvp73]

Hey Super6VT

Just a question as mine is doing the same. When it drops on idle, do you have the transmission in Park or Drive? Mine does it but only on Drive! Other than that, my car runs like a dream, except idling on drive (wondering whether transmission problem)! Feels like its going to die then as quick as it drops it comes up again.

Let us know

[Kernal]

Fuel filter

[Old Timer]

Hey Super6VT

Just a question as mine is doing the same. When it drops on idle, do you have the transmission in Park or Drive? Mine does it but only on Drive! Other than that, my car runs like a dream, except idling on drive (wondering whether transmission problem)! Feels like its going to die then as quick as it drops it comes up again.
Let us know

Lazy IAC valve ???

[TA 91 WA]

Hey Super6VT

Just a question as mine is doing the same. When it drops on idle, do you have the transmission in Park or Drive? Mine does it but only on Drive! Other than that, my car runs like a dream, except idling on drive (wondering whether transmission problem)! Feels like its going to die then as quick as it drops it comes up again.

Let us know

Same problem as me, but mine is a 3.8ltr. Replaced O2 sensors, plugs, leads, coils and module approx 5000km ago..

Hoses have been inspected and none look frayed or loose. Sorry to hijack, but I'm completely stumped as well.