My 1.6 GLXi is only firing on 3 cylinders. Only started in the past couple of days. I've checked the HT wiring and it all seems properly connected. It's definatly one of the cylinders out - not an irregular misfire. I think I can mell the unburnt fuel through the exhaust and I assume it's not wise to use the car until its sorted.

Anyone got any ideas what may be causing it?

AndyC

If the HT system is intact, I would put money on a dodgy spark plug.