sorry for the first post beening long and look for help

i have an issue with my lpg converted 3.3 grand voyager

the other day i was running on lpg and the car back fired twice in quick succession and the service engine soon light lit up, so i switched back to petrol but the revs were limited to 3800-4200 rpm and wouldnt run correctly, this was followed by smoke comming out of the exhaust which went away after about 1 mile.

i got home and the smoke returned for a short period i belive it was blueish, but now it dosent smoke at all.

the car will run fine on lpg and rev fully but it will not tick over when cold on petrol, but will after lpg has been run.

yesterday had the gv checked for codes but nothing came up even tho the service engine light is still on.

also the car has started to pop if i keep the revs upto 1000rpm after first starting,

done a few videos


starting on petrol
starting and attempting to run on petrol - YouTube

no smoke on petrol
no smoke running on petrol - YouTube

running on lpg
running on lpg - YouTube

running on lpg but switching to petrol
initially running on lpg and switching back to petrol - YouTube

popping on startup
DSCF2547 - YouTube (cant really hear the popping but you can hear when the sound goes off due to the popping)

been doing a bit of reading about the lpg backfire and seems these are common on single point systems also they can destroy the maf sensors but these are not present on the mk3 3.3 gv only a tps and a map sensor.

where would i find a tps and a map sensor in the uk as the local parts shop dont list the part nor can they find it. is it lickly either of these would be bad if the engine is running fine on lpg.

i have ordered new sparks and leads as well as a new airfilter and an obd usb reader to see what is happening when running.

would the crank sensor cause this sort of issue and where would i find a replacement in the uk as finding electrical parts over here for the gv is not as easy as i would have hoped

i was having an issue with stalling when accelerator was released so would this be a factor as well reguarding the problem

any help with this would be a appreciated

 

right some screenshots the fault code only shows after a stall but other wise it reports no fault











unpluged the map and still the same result fine when warm but will stall unless you apply throttle when starting i f no throttle applied it will just stall.

when cold the engine will not idle at all with out the throttle being applied