VZ 2005 Stutters when warm/running temp only

[tilaren]

Hi,
I have a VZ berlina auto 2005 3.6ltr

The car runs perfectly when its cold, but as soon as it hits running temp or a hot day, the engine stutters and looses all power.
It feels like it is starving for fuel/air or misfiring or something.
this effect lasts anywhere from 10-30 seconds before it regains its power.
No matter how soft or hard I press the accelerator the effect is always the same.
when its cold it runs and idles perfectly, but as soon as it reaches running temp, then it idles extremely rough(whole car rocks) and I loose the power.

I took it to ultra tune and describe the problem and they just said drop it in and well take a look. I'm currently moving house and have other commitments, so I cannot afford a professional fix at the moment.

Any one have any ideas on where to start, or know what the problem might be.

Any help would be greatly appreciated.

Thanks in advance

 

[diysv6]

Could it be an ignition coil breaking down when hot?

Can you disconnect each ignition coil in turn and see which one does not effect the idle?
That will indicate a coil or fuel injector is faulty.
Can you get the DTCs read at all?

 

[CalaisNQ]

Sounds like a faulty coil or two.
Have changed a few on vz and ve v6s, it makes it easier to find if you can get a hold of someone with a scan tool, as it can show which cylinder is missfiring.
Also has the fuel filter ever been changed? Had a friend with a rough running vz, we found the filter was fairly clogged, replacement fix his problem.

 

[tilaren]

ok thanks guys, will look into both of your suggestions.
Also another guy I work with mentioned it could also be the knock sensors.
I haven't had time to do anything myself, but hopefully in the next week or two I can start testing theories.

and sorry for late reply, as I mentioned, no time.


Thankyou.