So I have been running an EF tickford head with 30 thou off it, for the last while, with an AU MLS head gasket. (45 thou removed from quench area)
J3 Chip with 98RON tune

Suddenly its running rough, after several 1000 km of being ok.

I changed the plugs and it seemed to be ok for a while... they looked a wee bit scortched witch one might expect from higher compression and standard plugs.

But got maybe 100km more out of it and it seems like its missing and running s**t again.

Has anyone had issues with burning out valves?

Someone suggested a stuffed rotor button. Is that likely?
I do have a cheap assed Supercheap dizzy cap on it..

Just checked it out via holding a light cloth behind the exhaust.

Aside from running rich enough to fuel a prius travelling behind me.. no sucking.
Good sign.

Maybe the injectors need a going over??

Injectors were good. turned out to be a bung lead.. first time Ive ever seen one just die..

Good that you solved the problem. Many, many years ago in my youth, the leads were carbon in the middle, and they used to break, causing all sorts of problems.Then some bright spark (pun intended) found out that wire could be used......................

Hello,

Leads used to be wire, but that caused problems with Radio's.