Hi lee thanks for the link will read through that shortly.

Peter- these plugs what where recommended for that car platinum lpg plugs. Think their Bosch ones

I changed the plugs a last year or year before and car just wasn't happy at all.

Was told the car should be running the plugs that are fitted with it having lpg its been running fine since until the latest episode.

The guy is happy that their could an probably is a mechanical engine issue as he's also heard of issues from running lpg

Mainly I'd like to prove it for myself so I've not got a lot of work for issue to remain.

The misfire is present on both petrol and lpg yes.

As for those readings would it affect it having twin tail pipes?

It dies go into one centre box before splitting so I'm assuming not but its worth asking the question to be sure?