Hi all,
I have a 1.3 Yaris 2007 too converted to LPG, with a STAG QBox, STEFANELLI vaporiser and OMVL FAST injectors, which is the second Yaris I've had converted but this time with no noticeable loss of power on gas. £15 for 30L LPG tends to produce a constant 265 miles mostly urban driving, which is less than half the price of petrol here in the UK.
That said I've put in iridium plugs which are widely available now - given this is an older (yet still very interesting) thread - designed specifically for LPG - NGK were first, [part number: BKR6EIX-LPG, stock number 3356] and Denso followed shortly after, which are reportedly good for 60k miles.
sparkplugs.co.uk/ngk-iridium-spark-plug-bkr6eix-lpg
Basically the LPG plugs have a wider gap with a stronger core to give a bigger spark to ignite LPG while drawing less electrical power to fire. They also have a more heavy duty insulation around the central electrode.
