VX2 hesitation/miss at very low revs

[sixfootseven]

Hi all. Just registered, had a bunch of Holdens over the years, currently driving a VX2 V6 police pack with factory LPG system, 217km, that we bought a few weeks ago.

Just took it on its first decent drive, and emptied a full tank of LPG, and got 9.5L/100km, which is pretty amazing for NZ as we have no long highways around here.

At low revs, any gear, with "light acceleration" it hesitates and misses a few times.

This happens MUCH less with absolute nana-acceleration, and slightly less with moderate acceleration.

It is more noticeable on petrol than it is on LPG.

Idle on petrol is perfect. Idle on LPG is slightly rough sometimes.

Other than that, drives/runs great, and ~700km from a tank of LPG in NZ tells me its certainly burning the vast majority of its fuel well.

Where to start? Is this a simple airfilter-then-plugs-then-leads-then-coils replacement affair? Or does someone here recognise the symptoms as being something specific?

 

[Immortality]

I'd be looking at plugs and leads as a first call. LPG definitely needs really good spark. I prefer and use the Bosch lpg spec ignition leads even on petrol only cars.

Other basic service items can't hurt either, new air filter, clean the MAF and the TB.

 

[NeddyBear]

Our beast had that little miss and mainly noticeable while at the lights.
Guys here suggested we replace the throttle position sensor which seems to have fixed her right up.

 

[Commo Baba]

Had something similar. Mine was plugs.

 

[Caprice5L]

Also had something similar. EGR valve.

 

[mattw1992]

I'd be checking the spark system first. Leads, plugs and coil packs, also a VX will be getting of age where the DFI will need looking at, your systems match a faulty DFI.

 

[Dazza VU ute]

I agree with spark system. I had same issue & turned out to be my ignition leads.