evader

Hi all in honda land. I need some help. I have a 1992 CB4 Honda Asscot Innova (similar to an Accord) with a F20A DOHC PMG FI engine and the dame thing has got a miss around the 100km/hr (60mph). I have replaced the plugs, ignition leads, dist cap, rotor, coil and module, air and fuel filters, ECU temp sensor also tried a replacement ECU with no success. When the engine is cold it will miss then rev to approx 1800 rpm then returns to normal idle when engine is at operating temp. You can feel the miss when low speed only slight but at 100km/hr man you know it's there. Its getting to a stage where I will have to take to a mechanic with a rolling road to but if anyone has any ideas I welcome your opinion. Cheers from New Zealand