My van missfires more on gas than petrol. Have renewed plugs and leads. How do i check if the coil packs are working. When i took plugs out only no 4 was firing right 1 2 and 3 were almost white.It did require new plug leads

Ged, April 2009

Hi! I had the missfire problem for over a year. On the petrol only. Its an y reg convoy. I've known that there had been a problem with the catalyctic converter because of the noise but it ran smooth on lpg. Once I've replaced the converter it worked fine both on petrol and lpg. I think the petrol system was clogging up within the catalyctic converter and was sending a strange message to the engine. Sorry, don't know what to say about your problem. Just wanted to share my experience. I think the lpg system on mine is not the fctory made one, but according to the receipts got when I bought it, it was installed by West Yorkshire Autogass.
cheers, good luck

Vlad, April 2009

Sounds like your timing is out alot, cars and vans that run on gas and petrol should have a light tan on the end of the plugs if its running right! Sounds like its running to hot also you should notice that your using alot more fuel than usual!

Ian Mechanic, April 2009