I have a 04 transit 2.3l running necam system ,factory fitted by Ford. The problem is when the van switches over to lpg. It sounds like the engine is missing a cylinder. When the van is started on petrol, it fires and revs no problem. When it ticks over, there is a slight blip in the engine every so often when on tick over. It sounds like the engine is missing a cylinder for a second only.
I was thinking it could be a coil pack starting to break down. I know any fault is greater on gas compared to petrol.
Has any one any suggestions
Forgot to mention this happened when I removed and replaced the inlet manifold. The lpg was working 100% before that.