Thanks Robert, Dave, Howard, Phil and Neil - hell or high water I'm going to solve this. It's possible/likely it's dragged through some crook fuel as I don't drive the C60X much at all - for the drive last week I filled up one tank completely (at an alarming cost!!! BTW
) - there wasn't much in the tank at all. I've discovered an inline ryco-style fuel filter that's probably been there since Federation. It's a starting point. So I'll take all the advice on board and methodically go through it - I'm going to replace the plugs, condensor, coil and leads anyway - if I'm pulling out plugs etc I might as well do it. I love it being in top form - it's always been such a smooth, wonderful engine - I'm just hoping it's not a sticking valve - or worse... So I've made a list to follow from your input and about to get cracking. Been on the phone to Ross Prince who's saving the day. Thanks so much for your help with this - I'll keep you posted...