Leaderboard

Mine misses from the get go. The HLA's are working, oil is flowing from their bleed holes, valve springs in #1 are good, no sticking valves. Cam lobes and rockers and bearings are perfect. However, the spark plug is clean, whilst the others are sooty from the short running on cold start it's been doing lately. No valve gear noise of any kind, so that rules out the rocker gear. Your oily plugs are likely bad or broken valve stem seals, quite common in crossflows. You also could have an exhaust valve seat recessing, taking up the lash adjustment in the lifter and holding the valve off the seat as it heats up and expands. Mine? Still working on it.

Had something similar with the young blokes BF Turbo; it kept triggering a coil pack error in number one cylinder and running like a dog. Put nos plugs, coils, sensors etc in it to no avail (similar to your situation). Took it to an old school mechanic and he changed the inlet manifold gaskets and removed the engine hook and all is good. The old gaskets were so hard and perished that they would leak air when the motor heated up but were ok when it was cold.