Missfiring, occasional backfireing & hesitation on LPG

[dom14]

IMO its either an air leak or running lean they are the onlt 2 things
I can think of atm as to why a motor would back fire Ill add timing as well
so theres 3 things to look at.
Get the timing just of pinging and you'll be close to the ball park .
are you blowing the air cleaner box off yet??
Have you Y pieces instaed of Tees that will aid in water flow and less cavitation

It turns out the poor ignition due to spark plug gap being too high(or I think that's what it is 'cos narrowing the gap appeared to have fixed it). I was so sure there's an air leak somewhere, so kept looking for it, but couldn't find any vacuum leaks.
Besides that, the spark plugs in it aren't the factory recommended ones even though the specs are the same except the outside height of the plug and the gap. 0.5mm gap adjustment appears to be working for LPG.
I didn't bother to try it on petrol, but I'm pretty sure it won't be happy without adjusting the timing to around 10btdc or less.
It's not possible to fine tune for both fuels unless I employ a dual curve unit.
I've never invested on the dual curve unit, 'cos I thought it's less complicated to carry a second set of spark plugs & adjust the timing manually when it is necessary to switch to the other fuel. Of course that won't address the timing curve, but it's less complicated.
Adding more electronics on top of having an electronic dizzy in RB30 Patrol complicates things more I thought.

I'll clock the LPG economy again and see how it goes. If the economy is still bad, then I still have a problem.