Hey thanks for the reply:
The ‘quack’ is only on cold start, apparently a sticky starter motor…I am not too worried about it.
Yes the LPG system is definitely shoddy and badly wired.
The ‘pop’ is when in Petrol or LPG but never at high revs, only at low revs when accelerating.
I will try disconnecting the battery and reset.
At low rpm, the engine needs more fuel to be added when you open the throttle quickly (for various complicated reasons i won’t go into here) and too little extra fuel (called acceleration enrichment) results in a lean spike and in bad cases (AFR > ~ 16:1) misfires.
How is this solved?