That's great advice mate I have also thought of doing that. I will try it this arvo.
I can also smell fuel through the exhaust which tells me its getting into the chamber.
The plus where very oiled up also.
did you actually test the ignition with the spark plug removed, so you could see the spark in the plug gap? -- I was caught out by this an one time, didn't think to check the actual spark-plug, just pulled the lead and "tested" for ignition with another plug ... (Removing the plugs from the bottomless pits they sit in on the F4 is a bit of a Pita .. ) I thought that fairly new plugs could not possibly be the cause...
Mind you I only had a "running on 3 cylinders" problem .. It seems unlikely that all 4 plugs would fail at the same time--