4.0 LPG hot starting issue

I have a 4.0 fitted with LPG and from cold it starts okay and switches to LPG after about 5 minutes without any issues.

The problem I am having is when starting again when the engine is hot. If I start in petrol I am getting a very poor tickover and on occasions it has stalled.

If the engine is still hot should I just keep it on LPG? I have tried this a few times with some success but on other occasions I have had to switch to petrol for a few miles before it has worked okay in LPG.

This has been an intermittent problem, but now seems to be every day I am having an issue.

Any suggestions?

Thanks

If your having problems with both lpg and petrol i would start with the basics, try new plugs and leads as a starting point.