1.4 tu3jp (KFW) intermittent misfire

[Will97]

Have you thought about doing a compression test etc when cold? The misfire could be due to the start of a head gasket leak where water is seeping into one or two of the cylinders as the engine cools down and contracts, especially if it happens on startup then goes away as the engine warms up ... The engine expands as it warms up and therefore seals the leak until it contracts again.