Possible leak in the inlet manifold

[neobristol]

Hey guys having some problems with the dunnydore, its got ever such a slight rough idle, when on petrol (even worse on gas) I used to get hesitation only on gas before but its starting to become apparent on petrol now aswell, just had the fault codes checked by holden, and in the history were left & right O2 sensors high voltage so im assuming they are no longer faulty? Im leaning towards the idea of a leak somewhere in the inlet system, what are the usual suspects on a vx v6? As for the hesitation how likely is it to be the throttle position sensor? I also get a constant feeling of 'misfiring' in between 80-100km/h although having put the car on an oscilloscope i can conclude it is not an elctrical mis-fire. The car has new plugs gapped to 1.0mm (this is optimal for lpg) new quality champion leads, and 3 new coil packs, the people that fitted the gas have also fitted 6 new gas injectors.

Sorry it is abit of a long winded one, basically all the problems im having first started on lpg but have now migrated to petrol.

[vxcalais_01]

Hey guys having some problems with the dunnydore, its got ever such a slight rough idle, when on petrol (even worse on gas) I used to get hesitation only on gas before but its starting to become apparent on petrol now aswell, just had the fault codes checked by holden, and in the history were left & right O2 sensors high voltage so im assuming they are no longer faulty? Im leaning towards the idea of a leak somewhere in the inlet system, what are the usual suspects on a vx v6? As for the hesitation how likely is it to be the throttle position sensor? I also get a constant feeling of 'misfiring' in between 80-100km/h although having put the car on an oscilloscope i can conclude it is not an elctrical mis-fire. The car has new plugs gapped to 1.0mm (this is optimal for lpg) new quality champion leads, and 3 new coil packs, the people that fitted the gas have also fitted 6 new gas injectors.

Sorry it is abit of a long winded one, basically all the problems im having first started on lpg but have now migrated to petrol.

Firstly, 1mm is not optimal, its just too small. 1.3mm is the smallest you should go. If 1.5mm works without backfires, stay with 1.5mm. You now have a more consistent weaker spark instead of a longer stronger spark. Secondly, Champion do not make quality leads. The only good plugs they have which are some of the best are Champion Gold. Do not go a colder plug as standard plug is cold enough.

Recheck leads, plugs etc. Regap them to 1.3 at least. Alot of leads start playing up out of the box. LPG is more reliant on spark strength/quality thats why it is worse on gas.

When my inlet manifold gasket went, i found oil in the radiator.