Hi Peter although I have a pico I don't have first look so i can't comment from experience but there is definately a repeating pattern in both scope traces. But as you say, no cylinder is massively different from the rest. I would maybe guess at sticky valves or lifters, I have had some success with a 5 mile drive with engine flush on a couple of engines when other people would start taking them apart. I also think that engine would be ok with a 0w/40 oil. You mentioned the front pulley, not sure if they can cause this problem but is it possible to run the engine without it? The timing chain is at the back so that should be ok.