apbling wrote
.....but old caps...could this old cap be an issue?
Might indeed be an old cap issue. Definitely worth a look. I change my plug caps every few years and I always look for the non resistor type or at least the lowest value resistor caps I can find. If it's a resistor cap and you have a multimeter then set it to ohms and see what resistance you get between one side of the cap and the other. I have had caps that basically showed open circuit and somehow had a weak spark at the plug.
Dielectric grease is also good to smear on the top of the plug which clicks into the cap. Another cheap fix.
Good luck
