MINE DOES THE EXACT SAME THING !!!!!!!!!!!!!!!!!!!!
sometimes runs on gas sometimes stalls i had it fully serviced and everything!! its drivin me nuts!!
i use the gas on long drives and now i cant use it at all. i duno s**t about gas systems

i got ef xr8

only prob with vialle systems is there isnt much info on them so you kinda hit a brick wall.

if O2 sensor and the mixture adjuster on the convertor are working fine, possible elec fault or convertor fault.

the mixture adjusters on the convertors are problematic from what I hear (black dowicky with the 4 pin plug) thats in the convertor to the gas line to intake. should on key on engine off (with bonnet up) hear it make a (whiring) noise for a few secs then stop

Thank you guys
Hopefully this thread may help others cuz' I'm not the only one with a funny Ford!!

AU99: that 'black dowicky with the 4 pin plug' is the stepper valve which was playing up,Had to replace it but didn't totally fix the problem.
"only prob with vialle systems is there isnt much info on them so you kinda hit a brick wall." doesn't sound good...!
Will let you know about sensors plus other bits once The Local guy comes back.

lonfa

Things that were wrong/stuffed,There's a Big learn curve in all of this.....

Oxygen sensor(very high fuel usage...!),Wrong(standard) thermostat (when leaking head gasket was replaced) which buggered the converter ( when it froze) and put coolant through the system which stuffed the (newish second) stepper motor .

So proper (gas) Thermostat,Oxygen/water temp sensor (replace as a set) New Recond' converter ($700)[new ones not longer available] {can not use aftermarket one as everything has to be genuine for factory tickford LPG/computer to work....or so I was told} Second new stepper motor.

Outcome: everything running perfectly with Big increase in fuel (lpg/petrol) mileage.(450 kms per 60l LPG tank average-Not 290 kms!! like before)

Cost: not final yet but around $1500.(plus 20000 km's worth of petrol@$1.40 aver' per L)

why did it take so long? Had to find the Right place to do the work (The HARD Part ....and the time/money) >>>>

Donovan Ford, Merredin, WA-Top Notch work and Very Good people to deal with.

Things to be done: full gas tune,Get the bloody Roo damage fixed......Thank goodness for Bullbars,Another story...

Thank you to everyone for their help,This and other Ford forums have been
my BEST source of information.

Thanks Guys!!
lonfa