you've got a problem mate4, ours never changes over to petrol unless i do it manually (ours wont change to petrol even if its struggling or stalling) i'm having to bite the bullet and take outs to volvo to see if they can sort the problem

thanks for the info think i might start with getting lpg filters changed and see if it makes a difference,as i do not know if these have been done with the services cheers kev

This is a lack of fuel problem! Probable causes: LPG filter(s) need changing, LPG fuel distributor/regulator problem, LPG fuel pressure not set up properly - possibly a combination of all three! Fairly easy things for a dealer or an LPG indy to check. Cheers Jack

thanks jack,

BiFuel switching/cutout 

The deciding factor as to when the LPG switches on is coolant temperature , if your thermostat has failed and the engine is running cool this will explain the problem , i had this problem last week ...

It seems you need a new thermostat then which will increase the efficiency of your engine and cause the LPG to switch in much earlier ...

to be honest clan i cant fault it's initial switching i start it from cold and usually in the first 5 mins of driving it will switch to lpg, sometimes it will stop on it no probs others it will just randomly switch to petrol somtimes after 3 or 4 miles others after 10 or 12 miles