thats great mate. sounds like i weak spark, i have just brought some new ht leads, that might sort it, the plugs r 8 week old i think i set the gap at 9mm its running on gas, i wonder if gap is to biggg
LPG needs a hotter spark than petrol so a smaller gap is better than bigger one.
I run some old engines on LPG only and to make starting easier I set gap to 25 thou rather than 32 thou. thats inches not metric.
when I had mine converted to LPG, the installer (local LR Indy) changed the HT leads for magnacor and the plugs for iridium ones which, apparenlty, suit the lpg engine better.
At last service (about 3 weeks ago) plugs all nice & clean